CA2198612C - Epoxy adhesive composition - Google Patents
Epoxy adhesive composition Download PDFInfo
- Publication number
- CA2198612C CA2198612C CA002198612A CA2198612A CA2198612C CA 2198612 C CA2198612 C CA 2198612C CA 002198612 A CA002198612 A CA 002198612A CA 2198612 A CA2198612 A CA 2198612A CA 2198612 C CA2198612 C CA 2198612C
- Authority
- CA
- Canada
- Prior art keywords
- epoxy
- adhesive composition
- shear strength
- amine
- parts
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 239000000203 mixture Substances 0.000 title claims abstract description 76
- 229920006332 epoxy adhesive Polymers 0.000 title claims abstract description 26
- 150000001412 amines Chemical class 0.000 claims abstract description 33
- 239000003054 catalyst Substances 0.000 claims abstract description 21
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 21
- 239000003822 epoxy resin Substances 0.000 claims abstract description 18
- 229920000647 polyepoxide Polymers 0.000 claims abstract description 18
- 125000003700 epoxy group Chemical group 0.000 claims abstract description 9
- 230000001070 adhesive effect Effects 0.000 claims description 60
- 239000000853 adhesive Substances 0.000 claims description 59
- 229910052751 metal Inorganic materials 0.000 claims description 43
- 239000002184 metal Substances 0.000 claims description 43
- 239000004593 Epoxy Substances 0.000 claims description 37
- 230000006698 induction Effects 0.000 claims description 36
- 238000010438 heat treatment Methods 0.000 claims description 27
- 238000000034 method Methods 0.000 claims description 20
- 239000000758 substrate Substances 0.000 claims description 11
- 239000012745 toughening agent Substances 0.000 claims description 11
- 238000000576 coating method Methods 0.000 claims description 7
- 239000002685 polymerization catalyst Substances 0.000 claims description 7
- 239000011248 coating agent Substances 0.000 claims description 6
- 238000010998 test method Methods 0.000 claims description 6
- KAKZBPTYRLMSJV-UHFFFAOYSA-N vinyl-ethylene Natural products C=CC=C KAKZBPTYRLMSJV-UHFFFAOYSA-N 0.000 claims description 6
- 229920001577 copolymer Polymers 0.000 claims description 5
- 125000001495 ethyl group Chemical group [H]C([H])([H])C([H])([H])* 0.000 claims description 4
- 239000000314 lubricant Substances 0.000 claims description 4
- CWRORZJYSUFYHO-UHFFFAOYSA-N (3z)-3-diazobicyclo[2.2.2]octane Chemical compound C1CC2C(=[N+]=[N-])CC1CC2 CWRORZJYSUFYHO-UHFFFAOYSA-N 0.000 claims description 3
- 150000002500 ions Chemical class 0.000 claims description 2
- 229910001914 chlorine tetroxide Inorganic materials 0.000 claims 1
- VLTRZXGMWDSKGL-UHFFFAOYSA-M perchlorate Chemical compound [O-]Cl(=O)(=O)=O VLTRZXGMWDSKGL-UHFFFAOYSA-M 0.000 claims 1
- 238000012360 testing method Methods 0.000 description 25
- 150000002118 epoxides Chemical group 0.000 description 19
- GYZLOYUZLJXAJU-UHFFFAOYSA-N diglycidyl ether Chemical compound C1OC1COCC1CO1 GYZLOYUZLJXAJU-UHFFFAOYSA-N 0.000 description 15
- 238000002156 mixing Methods 0.000 description 14
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 13
- IISBACLAFKSPIT-UHFFFAOYSA-N bisphenol A Chemical compound C=1C=C(O)C=CC=1C(C)(C)C1=CC=C(O)C=C1 IISBACLAFKSPIT-UHFFFAOYSA-N 0.000 description 13
- RAXXELZNTBOGNW-UHFFFAOYSA-N imidazole Natural products C1=CNC=N1 RAXXELZNTBOGNW-UHFFFAOYSA-N 0.000 description 9
- 229920001971 elastomer Polymers 0.000 description 8
- 239000005060 rubber Substances 0.000 description 8
- 150000003839 salts Chemical class 0.000 description 8
- -1 aliphatic amines Chemical class 0.000 description 7
- 239000002245 particle Substances 0.000 description 7
- ZWEHNKRNPOVVGH-UHFFFAOYSA-N 2-Butanone Chemical compound CCC(C)=O ZWEHNKRNPOVVGH-UHFFFAOYSA-N 0.000 description 6
- 239000002253 acid Substances 0.000 description 6
- 229910021486 amorphous silicon dioxide Inorganic materials 0.000 description 6
- 150000004985 diamines Chemical class 0.000 description 6
- 239000000539 dimer Substances 0.000 description 6
- 229910021485 fumed silica Inorganic materials 0.000 description 6
- 239000011521 glass Substances 0.000 description 6
- 239000000463 material Substances 0.000 description 6
- 230000009257 reactivity Effects 0.000 description 6
- 239000000243 solution Substances 0.000 description 6
- 239000004952 Polyamide Substances 0.000 description 5
- 239000005062 Polybutadiene Substances 0.000 description 5
- 239000011324 bead Substances 0.000 description 5
- 239000011575 calcium Substances 0.000 description 5
- 239000007795 chemical reaction product Substances 0.000 description 5
- 239000003085 diluting agent Substances 0.000 description 5
- 229920002647 polyamide Polymers 0.000 description 5
- 229920002857 polybutadiene Polymers 0.000 description 5
- IJZZYQTVHBGRHO-UHFFFAOYSA-N 1-[2-(2-propoxyethoxy)ethoxy]propane-1,3-diamine Chemical compound CCCOCCOCCOC(N)CCN IJZZYQTVHBGRHO-UHFFFAOYSA-N 0.000 description 4
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- 229910000831 Steel Inorganic materials 0.000 description 4
- PPBRXRYQALVLMV-UHFFFAOYSA-N Styrene Chemical compound C=CC1=CC=CC=C1 PPBRXRYQALVLMV-UHFFFAOYSA-N 0.000 description 4
- ORLQHILJRHBSAY-UHFFFAOYSA-N [1-(hydroxymethyl)cyclohexyl]methanol Chemical compound OCC1(CO)CCCCC1 ORLQHILJRHBSAY-UHFFFAOYSA-N 0.000 description 4
- 239000002671 adjuvant Substances 0.000 description 4
- 125000003118 aryl group Chemical group 0.000 description 4
- PXKLMJQFEQBVLD-UHFFFAOYSA-N bisphenol F Chemical compound C1=CC(O)=CC=C1CC1=CC=C(O)C=C1 PXKLMJQFEQBVLD-UHFFFAOYSA-N 0.000 description 4
- 150000001875 compounds Chemical class 0.000 description 4
- 238000001816 cooling Methods 0.000 description 4
- 239000006185 dispersion Substances 0.000 description 4
- 229920000578 graft copolymer Polymers 0.000 description 4
- 239000011777 magnesium Substances 0.000 description 4
- 239000000178 monomer Substances 0.000 description 4
- 239000004033 plastic Substances 0.000 description 4
- 229920003023 plastic Polymers 0.000 description 4
- 229920000642 polymer Polymers 0.000 description 4
- GHMLBKRAJCXXBS-UHFFFAOYSA-N resorcinol Chemical compound OC1=CC=CC(O)=C1 GHMLBKRAJCXXBS-UHFFFAOYSA-N 0.000 description 4
- 239000010959 steel Substances 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- DSROZUMNVRXZNO-UHFFFAOYSA-K tris[(1-naphthalen-1-yl-3-phenylnaphthalen-2-yl)oxy]alumane Chemical compound C=1C=CC=CC=1C=1C=C2C=CC=CC2=C(C=2C3=CC=CC=C3C=CC=2)C=1O[Al](OC=1C(=C2C=CC=CC2=CC=1C=1C=CC=CC=1)C=1C2=CC=CC=C2C=CC=1)OC(C(=C1C=CC=CC1=C1)C=2C3=CC=CC=C3C=CC=2)=C1C1=CC=CC=C1 DSROZUMNVRXZNO-UHFFFAOYSA-K 0.000 description 4
- KUBDPQJOLOUJRM-UHFFFAOYSA-N 2-(chloromethyl)oxirane;4-[2-(4-hydroxyphenyl)propan-2-yl]phenol Chemical compound ClCC1CO1.C=1C=C(O)C=CC=1C(C)(C)C1=CC=C(O)C=C1 KUBDPQJOLOUJRM-UHFFFAOYSA-N 0.000 description 3
- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical compound O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 description 3
- QYKIQEUNHZKYBP-UHFFFAOYSA-N Vinyl ether Chemical compound C=COC=C QYKIQEUNHZKYBP-UHFFFAOYSA-N 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- RTZKZFJDLAIYFH-UHFFFAOYSA-N ether Substances CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 3
- 239000000945 filler Substances 0.000 description 3
- LNEPOXFFQSENCJ-UHFFFAOYSA-N haloperidol Chemical compound C1CC(O)(C=2C=CC(Cl)=CC=2)CCN1CCCC(=O)C1=CC=C(F)C=C1 LNEPOXFFQSENCJ-UHFFFAOYSA-N 0.000 description 3
- 229910052749 magnesium Inorganic materials 0.000 description 3
- 229910021645 metal ion Inorganic materials 0.000 description 3
- 229920000058 polyacrylate Polymers 0.000 description 3
- 229920000193 polymethacrylate Polymers 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- 229920005989 resin Polymers 0.000 description 3
- 239000011347 resin Substances 0.000 description 3
- 229960000834 vinyl ether Drugs 0.000 description 3
- NIXOWILDQLNWCW-UHFFFAOYSA-M Acrylate Chemical group [O-]C(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-M 0.000 description 2
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 2
- 229910001335 Galvanized steel Inorganic materials 0.000 description 2
- QIGBRXMKCJKVMJ-UHFFFAOYSA-N Hydroquinone Chemical compound OC1=CC=C(O)C=C1 QIGBRXMKCJKVMJ-UHFFFAOYSA-N 0.000 description 2
- 241000976924 Inca Species 0.000 description 2
- 229920002633 Kraton (polymer) Polymers 0.000 description 2
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 2
- 229920009204 Methacrylate-butadiene-styrene Polymers 0.000 description 2
- ISWSIDIOOBJBQZ-UHFFFAOYSA-N Phenol Chemical compound OC1=CC=CC=C1 ISWSIDIOOBJBQZ-UHFFFAOYSA-N 0.000 description 2
- JUJWROOIHBZHMG-UHFFFAOYSA-N Pyridine Chemical compound C1=CC=NC=C1 JUJWROOIHBZHMG-UHFFFAOYSA-N 0.000 description 2
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- 125000000217 alkyl group Chemical group 0.000 description 2
- 150000004945 aromatic hydrocarbons Chemical class 0.000 description 2
- LKAVYBZHOYOUSX-UHFFFAOYSA-N buta-1,3-diene;2-methylprop-2-enoic acid;styrene Chemical compound C=CC=C.CC(=C)C(O)=O.C=CC1=CC=CC=C1 LKAVYBZHOYOUSX-UHFFFAOYSA-N 0.000 description 2
- ZCCIPPOKBCJFDN-UHFFFAOYSA-N calcium nitrate Chemical compound [Ca+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O ZCCIPPOKBCJFDN-UHFFFAOYSA-N 0.000 description 2
- OSGAYBCDTDRGGQ-UHFFFAOYSA-L calcium sulfate Chemical compound [Ca+2].[O-]S([O-])(=O)=O OSGAYBCDTDRGGQ-UHFFFAOYSA-L 0.000 description 2
- 150000001735 carboxylic acids Chemical class 0.000 description 2
- YCIMNLLNPGFGHC-UHFFFAOYSA-N catechol Chemical compound OC1=CC=CC=C1O YCIMNLLNPGFGHC-UHFFFAOYSA-N 0.000 description 2
- 235000014113 dietary fatty acids Nutrition 0.000 description 2
- 239000000194 fatty acid Substances 0.000 description 2
- 229930195729 fatty acid Natural products 0.000 description 2
- 150000004665 fatty acids Chemical class 0.000 description 2
- 239000008397 galvanized steel Substances 0.000 description 2
- 238000011065 in-situ storage Methods 0.000 description 2
- 125000005397 methacrylic acid ester group Chemical group 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- TVMXDCGIABBOFY-UHFFFAOYSA-N octane Chemical compound CCCCCCCC TVMXDCGIABBOFY-UHFFFAOYSA-N 0.000 description 2
- 239000003921 oil Substances 0.000 description 2
- 150000002989 phenols Chemical class 0.000 description 2
- 229920000962 poly(amidoamine) Polymers 0.000 description 2
- 229920000728 polyester Polymers 0.000 description 2
- 230000005855 radiation Effects 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 239000003381 stabilizer Substances 0.000 description 2
- 229920001897 terpolymer Polymers 0.000 description 2
- SLBDZIKCTKBNEB-UHFFFAOYSA-N 1,1-diphenylpentane-2,2-diol Chemical class C=1C=CC=CC=1C(C(O)(O)CCC)C1=CC=CC=C1 SLBDZIKCTKBNEB-UHFFFAOYSA-N 0.000 description 1
- IBZYZLISHMZNDO-UHFFFAOYSA-N 1,3,3-triphenylpropane-1,1-diol Chemical class C=1C=CC=CC=1C(O)(O)CC(C=1C=CC=CC=1)C1=CC=CC=C1 IBZYZLISHMZNDO-UHFFFAOYSA-N 0.000 description 1
- DMPLZAKSSGHHJR-UHFFFAOYSA-N 1,4,4-triphenylbutane-1,1-diol Chemical compound C=1C=CC=CC=1C(O)(O)CCC(C=1C=CC=CC=1)C1=CC=CC=C1 DMPLZAKSSGHHJR-UHFFFAOYSA-N 0.000 description 1
- DQNSRQYYCSXZDF-UHFFFAOYSA-N 1,4-bis(ethenoxymethyl)cyclohexane Chemical compound C=COCC1CCC(COC=C)CC1 DQNSRQYYCSXZDF-UHFFFAOYSA-N 0.000 description 1
- WBBFPZUNWQVYGR-UHFFFAOYSA-N 1,5,5-triphenylpentane-1,1-diol Chemical compound C=1C=CC=CC=1C(O)(O)CCCC(C=1C=CC=CC=1)C1=CC=CC=C1 WBBFPZUNWQVYGR-UHFFFAOYSA-N 0.000 description 1
- ZPANWZBSGMDWON-UHFFFAOYSA-N 1-[(2-hydroxynaphthalen-1-yl)methyl]naphthalen-2-ol Chemical compound C1=CC=C2C(CC3=C4C=CC=CC4=CC=C3O)=C(O)C=CC2=C1 ZPANWZBSGMDWON-UHFFFAOYSA-N 0.000 description 1
- WAEOXIOXMKNFLQ-UHFFFAOYSA-N 1-methyl-4-prop-2-enylbenzene Chemical group CC1=CC=C(CC=C)C=C1 WAEOXIOXMKNFLQ-UHFFFAOYSA-N 0.000 description 1
- RNFJDJUURJAICM-UHFFFAOYSA-N 2,2,4,4,6,6-hexaphenoxy-1,3,5-triaza-2$l^{5},4$l^{5},6$l^{5}-triphosphacyclohexa-1,3,5-triene Chemical compound N=1P(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP=1(OC=1C=CC=CC=1)OC1=CC=CC=C1 RNFJDJUURJAICM-UHFFFAOYSA-N 0.000 description 1
- CISIJYCKDJSTMX-UHFFFAOYSA-N 2,2-dichloroethenylbenzene Chemical compound ClC(Cl)=CC1=CC=CC=C1 CISIJYCKDJSTMX-UHFFFAOYSA-N 0.000 description 1
- LCVCUJWKJNFDMY-UHFFFAOYSA-N 2,2-diphenylpropane-1,1-diol Chemical class C=1C=CC=CC=1C(C(O)O)(C)C1=CC=CC=C1 LCVCUJWKJNFDMY-UHFFFAOYSA-N 0.000 description 1
- WORVYYDNYUXZBS-UHFFFAOYSA-N 2,4,6-tris(dimethylamino)-3-methylphenol Chemical compound CN(C)C1=CC(N(C)C)=C(O)C(N(C)C)=C1C WORVYYDNYUXZBS-UHFFFAOYSA-N 0.000 description 1
- SHKUUQIDMUMQQK-UHFFFAOYSA-N 2-[4-(oxiran-2-ylmethoxy)butoxymethyl]oxirane Chemical class C1OC1COCCCCOCC1CO1 SHKUUQIDMUMQQK-UHFFFAOYSA-N 0.000 description 1
- MHINGNWUUYJOSW-UHFFFAOYSA-N 2-chlorobut-1-enylbenzene Chemical compound CCC(Cl)=CC1=CC=CC=C1 MHINGNWUUYJOSW-UHFFFAOYSA-N 0.000 description 1
- SBYMUDUGTIKLCR-UHFFFAOYSA-N 2-chloroethenylbenzene Chemical compound ClC=CC1=CC=CC=C1 SBYMUDUGTIKLCR-UHFFFAOYSA-N 0.000 description 1
- KJWCYJRUDVTTGJ-UHFFFAOYSA-N 2-ethyl-2-(hydroxymethyl)propane-1,3-diol;pent-1-ene Chemical compound CCCC=C.CCCC=C.CCC(CO)(CO)CO KJWCYJRUDVTTGJ-UHFFFAOYSA-N 0.000 description 1
- CEBRPXLXYCFYGU-UHFFFAOYSA-N 3-methylbut-1-enylbenzene Chemical compound CC(C)C=CC1=CC=CC=C1 CEBRPXLXYCFYGU-UHFFFAOYSA-N 0.000 description 1
- RXNYJUSEXLAVNQ-UHFFFAOYSA-N 4,4'-Dihydroxybenzophenone Chemical compound C1=CC(O)=CC=C1C(=O)C1=CC=C(O)C=C1 RXNYJUSEXLAVNQ-UHFFFAOYSA-N 0.000 description 1
- VPWNQTHUCYMVMZ-UHFFFAOYSA-N 4,4'-sulfonyldiphenol Chemical compound C1=CC(O)=CC=C1S(=O)(=O)C1=CC=C(O)C=C1 VPWNQTHUCYMVMZ-UHFFFAOYSA-N 0.000 description 1
- NMIQMDZCTIANOF-UHFFFAOYSA-N 4,4-diphenylbutane-2,2-diol Chemical class C=1C=CC=CC=1C(CC(O)(O)C)C1=CC=CC=C1 NMIQMDZCTIANOF-UHFFFAOYSA-N 0.000 description 1
- QOHHOCDXTLIHPG-UHFFFAOYSA-N 4,4-diphenylcyclohexane-1,1-diol Chemical compound C1CC(O)(O)CCC1(C=1C=CC=CC=1)C1=CC=CC=C1 QOHHOCDXTLIHPG-UHFFFAOYSA-N 0.000 description 1
- FVCSARBUZVPSQF-UHFFFAOYSA-N 5-(2,4-dioxooxolan-3-yl)-7-methyl-3a,4,5,7a-tetrahydro-2-benzofuran-1,3-dione Chemical compound C1C(C(OC2=O)=O)C2C(C)=CC1C1C(=O)COC1=O FVCSARBUZVPSQF-UHFFFAOYSA-N 0.000 description 1
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- BRLQWZUYTZBJKN-UHFFFAOYSA-N Epichlorohydrin Chemical compound ClCC1CO1 BRLQWZUYTZBJKN-UHFFFAOYSA-N 0.000 description 1
- 101000878457 Macrocallista nimbosa FMRFamide Proteins 0.000 description 1
- LSDPWZHWYPCBBB-UHFFFAOYSA-N Methanethiol Chemical compound SC LSDPWZHWYPCBBB-UHFFFAOYSA-N 0.000 description 1
- WNUWQJKOHJDGLT-UHFFFAOYSA-N OC(C1=C(C=CC=C1)C)(C(C1=CC=CC=C1)C1=CC=CC=C1)O Chemical compound OC(C1=C(C=CC=C1)C)(C(C1=CC=CC=C1)C1=CC=CC=C1)O WNUWQJKOHJDGLT-UHFFFAOYSA-N 0.000 description 1
- VCJSLZRWRDXFIZ-UHFFFAOYSA-N OC1(CCC(CC1)C(C1CCCCC1)(C1=CC=CC=C1)C1=CC=CC=C1)O Chemical compound OC1(CCC(CC1)C(C1CCCCC1)(C1=CC=CC=C1)C1=CC=CC=C1)O VCJSLZRWRDXFIZ-UHFFFAOYSA-N 0.000 description 1
- YOAJZAXENKRXAB-UHFFFAOYSA-N OC1=C(C(=C(C=C1)C)C(C1=CC=CC=C1)C1=CC=CC=C1)O Chemical compound OC1=C(C(=C(C=C1)C)C(C1=CC=CC=C1)C1=CC=CC=C1)O YOAJZAXENKRXAB-UHFFFAOYSA-N 0.000 description 1
- 229910019142 PO4 Inorganic materials 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- 239000004642 Polyimide Substances 0.000 description 1
- 239000004721 Polyphenylene oxide Substances 0.000 description 1
- 239000004823 Reactive adhesive Substances 0.000 description 1
- BLRPTPMANUNPDV-UHFFFAOYSA-N Silane Chemical compound [SiH4] BLRPTPMANUNPDV-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 239000007983 Tris buffer Substances 0.000 description 1
- 229920001807 Urea-formaldehyde Polymers 0.000 description 1
- 125000005396 acrylic acid ester group Chemical group 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 125000001931 aliphatic group Chemical group 0.000 description 1
- 150000005215 alkyl ethers Chemical group 0.000 description 1
- XYLMUPLGERFSHI-UHFFFAOYSA-N alpha-Methylstyrene Chemical compound CC(=C)C1=CC=CC=C1 XYLMUPLGERFSHI-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 150000004982 aromatic amines Chemical class 0.000 description 1
- 230000000712 assembly Effects 0.000 description 1
- 238000000429 assembly Methods 0.000 description 1
- 239000000440 bentonite Substances 0.000 description 1
- 229910000278 bentonite Inorganic materials 0.000 description 1
- SVPXDRXYRYOSEX-UHFFFAOYSA-N bentoquatam Chemical compound O.O=[Si]=O.O=[Al]O[Al]=O SVPXDRXYRYOSEX-UHFFFAOYSA-N 0.000 description 1
- 229920001400 block copolymer Polymers 0.000 description 1
- 239000011449 brick Substances 0.000 description 1
- MPMBRWOOISTHJV-UHFFFAOYSA-N but-1-enylbenzene Chemical compound CCC=CC1=CC=CC=C1 MPMBRWOOISTHJV-UHFFFAOYSA-N 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 159000000007 calcium salts Chemical class 0.000 description 1
- PUQLFUHLKNBKQQ-UHFFFAOYSA-L calcium;trifluoromethanesulfonate Chemical compound [Ca+2].[O-]S(=O)(=O)C(F)(F)F.[O-]S(=O)(=O)C(F)(F)F PUQLFUHLKNBKQQ-UHFFFAOYSA-L 0.000 description 1
- 239000006229 carbon black Substances 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 235000019646 color tone Nutrition 0.000 description 1
- 239000007859 condensation product Substances 0.000 description 1
- 239000011258 core-shell material Substances 0.000 description 1
- 239000002173 cutting fluid Substances 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
- VEIOBOXBGYWJIT-UHFFFAOYSA-N cyclohexane;methanol Chemical compound OC.OC.C1CCCCC1 VEIOBOXBGYWJIT-UHFFFAOYSA-N 0.000 description 1
- NJJFVOQXYCEZLO-UHFFFAOYSA-N dialuminum;triberyllium;dioxido(oxo)silane Chemical compound [Be+2].[Be+2].[Be+2].[Al+3].[Al+3].[O-][Si]([O-])=O.[O-][Si]([O-])=O.[O-][Si]([O-])=O.[O-][Si]([O-])=O.[O-][Si]([O-])=O.[O-][Si]([O-])=O NJJFVOQXYCEZLO-UHFFFAOYSA-N 0.000 description 1
- 150000001993 dienes Chemical class 0.000 description 1
- 238000001938 differential scanning calorimetry curve Methods 0.000 description 1
- 125000005442 diisocyanate group Chemical group 0.000 description 1
- XXBDWLFCJWSEKW-UHFFFAOYSA-N dimethylbenzylamine Chemical compound CN(C)CC1=CC=CC=C1 XXBDWLFCJWSEKW-UHFFFAOYSA-N 0.000 description 1
- 150000002009 diols Chemical class 0.000 description 1
- PVAONLSZTBKFKM-UHFFFAOYSA-N diphenylmethanediol Chemical class C=1C=CC=CC=1C(O)(O)C1=CC=CC=C1 PVAONLSZTBKFKM-UHFFFAOYSA-N 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 125000001033 ether group Chemical group 0.000 description 1
- 150000002170 ethers Chemical class 0.000 description 1
- 229940052303 ethers for general anesthesia Drugs 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 239000003063 flame retardant Substances 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- 125000000524 functional group Chemical group 0.000 description 1
- 239000003365 glass fiber Substances 0.000 description 1
- 230000009477 glass transition Effects 0.000 description 1
- 239000002241 glass-ceramic Substances 0.000 description 1
- VOZRXNHHFUQHIL-UHFFFAOYSA-N glycidyl methacrylate Chemical compound CC(=C)C(=O)OCC1CO1 VOZRXNHHFUQHIL-UHFFFAOYSA-N 0.000 description 1
- 125000000623 heterocyclic group Chemical group 0.000 description 1
- 150000002483 hydrogen compounds Chemical class 0.000 description 1
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 1
- WGCNASOHLSPBMP-UHFFFAOYSA-N hydroxyacetaldehyde Natural products OCC=O WGCNASOHLSPBMP-UHFFFAOYSA-N 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 239000012784 inorganic fiber Substances 0.000 description 1
- 230000002452 interceptive effect Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000004850 liquid epoxy resins (LERs) Substances 0.000 description 1
- 150000002734 metacrylic acid derivatives Chemical class 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- UQKAOOAFEFCDGT-UHFFFAOYSA-N n,n-dimethyloctan-1-amine Chemical compound CCCCCCCCN(C)C UQKAOOAFEFCDGT-UHFFFAOYSA-N 0.000 description 1
- SLCVBVWXLSEKPL-UHFFFAOYSA-N neopentyl glycol Chemical compound OCC(C)(C)CO SLCVBVWXLSEKPL-UHFFFAOYSA-N 0.000 description 1
- 229920003986 novolac Polymers 0.000 description 1
- 150000002894 organic compounds Chemical class 0.000 description 1
- 125000000466 oxiranyl group Chemical group 0.000 description 1
- 239000003973 paint Substances 0.000 description 1
- 235000021317 phosphate Nutrition 0.000 description 1
- 150000003013 phosphoric acid derivatives Chemical class 0.000 description 1
- 125000005498 phthalate group Chemical class 0.000 description 1
- 239000000049 pigment Substances 0.000 description 1
- 239000004014 plasticizer Substances 0.000 description 1
- 229920001485 poly(butyl acrylate) polymer Polymers 0.000 description 1
- 229920003229 poly(methyl methacrylate) Polymers 0.000 description 1
- 229920006122 polyamide resin Polymers 0.000 description 1
- 239000004417 polycarbonate Substances 0.000 description 1
- 229920000515 polycarbonate Polymers 0.000 description 1
- 229920000570 polyether Polymers 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 229920001721 polyimide Polymers 0.000 description 1
- 239000004926 polymethyl methacrylate Substances 0.000 description 1
- ODGAOXROABLFNM-UHFFFAOYSA-N polynoxylin Chemical compound O=C.NC(N)=O ODGAOXROABLFNM-UHFFFAOYSA-N 0.000 description 1
- 229920002635 polyurethane Polymers 0.000 description 1
- 239000004814 polyurethane Substances 0.000 description 1
- HJWLCRVIBGQPNF-UHFFFAOYSA-N prop-2-enylbenzene Chemical compound C=CCC1=CC=CC=C1 HJWLCRVIBGQPNF-UHFFFAOYSA-N 0.000 description 1
- UMJSCPRVCHMLSP-UHFFFAOYSA-N pyridine Natural products COC1=CC=CN=C1 UMJSCPRVCHMLSP-UHFFFAOYSA-N 0.000 description 1
- 238000005057 refrigeration Methods 0.000 description 1
- 239000012779 reinforcing material Substances 0.000 description 1
- 238000007142 ring opening reaction Methods 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 229910000077 silane Inorganic materials 0.000 description 1
- 229910002027 silica gel Inorganic materials 0.000 description 1
- 239000000741 silica gel Substances 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 229920002050 silicone resin Polymers 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 239000000454 talc Substances 0.000 description 1
- 229910052623 talc Inorganic materials 0.000 description 1
- 150000003512 tertiary amines Chemical class 0.000 description 1
- 229920001169 thermoplastic Polymers 0.000 description 1
- 239000004416 thermosoftening plastic Substances 0.000 description 1
- 239000013008 thixotropic agent Substances 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 239000010936 titanium Substances 0.000 description 1
- 239000004408 titanium dioxide Substances 0.000 description 1
- IMFACGCPASFAPR-UHFFFAOYSA-N tributylamine Chemical compound CCCCN(CCCC)CCCC IMFACGCPASFAPR-UHFFFAOYSA-N 0.000 description 1
- 239000013638 trimer Substances 0.000 description 1
- BPSIOYPQMFLKFR-UHFFFAOYSA-N trimethoxy-[3-(oxiran-2-ylmethoxy)propyl]silane Chemical compound CO[Si](OC)(OC)CCCOCC1CO1 BPSIOYPQMFLKFR-UHFFFAOYSA-N 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
Landscapes
- Adhesives Or Adhesive Processes (AREA)
- Epoxy Resins (AREA)
Abstract
A curable, structural epoxy adhesive composition comprising two parts is provided. The first part comprises an amine curing agent and a catalyst; the second part comprises an epoxy resin having an average epoxide functionality of greater than one.
Description
WO 96109352 .
-PCTYtTS95/I 1900 EPOXY ADHESIVE COMPOSITION
FIELD OF THE INVENTION
The present invention relates to a thermally curable two part epoxy composition. The invention also relates to a two part epoxy adhesive made from the epoxy composition.
BACKGROUND OF THE INVENTION
Epoxy compositions are used widely in industry as adhesives, paints, and coatings for a number of applications. Epoxy adhesives are particularly useful for bonding metal surfaces together to provide strong structural bonds.
Structural epoxy adhesives have replaced spot welding and other methods of mechanical fastening in many industrial applications, such as in automotive assembly plants.
In some applications, it is often desirable to induction cure an epoxy adhesive composition for a short period of time so that the adhesive develops a green strength sufficient to bond metal surfaces. The induction cure generally involves a short exposure to radio frequency energy, on the order of magnitude of less than a minute, and often less than about 10 seconds, which generates heat in the metal parts to start the curing reaction. During this time, the epoxy adhesive catalyst needs to be activated to start the curing of the adhesive. Curing of the adhesive to its final state, i.e., a structural adhesive, is usually done in a subsequent oven bake.
Catalysts which have sufficient reactivity for induction curing often have a very limited pot Life; other catalysts may not effect sufficient curing to build the desired green strength during the induction heating cycle. It is desirable for the epoxy adhesive to build a strong, robust bond to the metal surface, usually through an oily coating of a mill oil, cutting fluid, draw oil, or a combination thereof. A
bond is referred to as robust if the bond breaks apart cohesively at high shear values when tested in an overlap shear test. The bonds may break in three different modes:
(1) the adhesive splits apart, leaving portions of the adhesive adhered to both metal surfaces in a cohesive failure mode; (2) the adhesive pulls away from either metal surfaces in an adhesive failure mode, or (3) a combination of adhesive and cohesive failure. Optimally, the adhesive fails in either the cohesive failure mode, or a combination of adhesive and cohesive failure.
There remains an ongoing need for improved epoxy adhesives that build robust, cohesive failure bonds to oily metals.
SL>ZvIMARY OF THE INVENTION
The present invention provides an epoxy catalyst comprising:
(i) an inorganic metal salt; and (ii) an epoxy polymerization catalyst. In a preferred embodiment the epoxy catalyst comprises a calcium salt and a non-sterically hindered tertiary amine such as dimethylbenzyl amine, dimethyl octyl amine, tributyl amine, diazobicyclo-(2,2,2)-octane and tris-2,4,6,-(dimethylaminomethyl)phenol.
The invention also provides an amine curing agent for epoxy resins comprising:
(i) the epoxy catalyst; and (ii) an amine curing agent.
The invention also provides a two-part amine curing epoxy composition that is capable of bonding to oily metal surfaces to form robust, structural bonds, comprising:
(I) a first part comprising:
an epoxy resin curing agent comprising:
(i) a catalytically effective amount of the epoxy catalyst having an inorganic metal salt; and an epoxy homopolymerization catalyst; and (ii) an amine curing agent; and (II) a second part comprising an epoxy resin having an average epoxide functionality of greater than one.
Preferably, the adhesive composition further includes a toughening agent compatible with the epoxy composition.
The present invention also provides a method of adhering to an oily metal substrate comprising applying a curable, structural epoxy adhesive , composition to an oily metal substrate.
.. _2-WO 96109352 f3 PCT/US95/I1900 DETAILED DESCRIPTION
The epoxy compositions of the invention are provided in a two part system in which the first part comprises a catalyst and an amine curing agent, and the second part comprises the epoxide.
The catalyst of the invention comprises a metal salt and a compound that is effective in lowering the first peak exotherm on curing of the epoxy composition as determined on a differential scanning calorimeter (DSC) at a heating rate of 20°C per minute. Preferably, the first peak exotherm is lowered by at least 20°C and more preferably by at least 3S°C as compared to compositions having only the metal salt, only the catalyst, or neither. Preferably, the curing agent will also erect a lowering of the second peak exotherm temperature, and most preferably, the second peak exotherm is lowered to less than about 250°C.
The invention provides a method of adhering to an oily metal substrate comprising applying a curable, structural epoxy adhesive composition to an oily metal substrate, wherein said curable, structural epoxy adhesive composition comprises two parts, the first part comprising:
(a) an epoxy catalyst comprising:
(i) a Ca+Z salt; and (ii) an epoxy polymerization catalyst having the structure of formula (I):
R~
R4 ~ CI) wherein R' is H or -CH3 .
R2 is -CHNRsR6 and R5 and R6 are independently selected from -CH3 and -y CH2CH3;
R3 and R4 independently may be present or absent, when present R3 and R4 are -CHNRsR6 and Rs and R6 are independently selected from -CH3 and -CH2CH3;
and (b) an amine curing agent; and the second part comprising an epoxy resin having an average epoxide functionality of greater than one. In one embodiment, Rl is H; in another Rz is -CHN(CH3)2, and in a third R3 and R4 are present and each of Ra, R3, and R4 is -CHN(CH3)Z. In another embodiment,the structure of formula (I) is tris 2,4,6-(dimethylaminomethyl)phenol. In a preferred embodiment, every epoxy polymerization catalyst that is present in the composition has the structure of formula (n.
In one embodiment, the adhesive composition has an overlap shear strength as measured by the test method Initial Shear Strength After Induction Heating for Examples 3 and 19 (described below) of at least 0.2 MPa after induction cure plus 1 hour of room temperature cure; in a preferred embodiment the overlap shear strength is at least 0.5 MPa.
In another embodiment, the adhesive composition has an overlap shear strength as measured by the test method Lap Shear Strength (described below) of at least 9 MPa and cohesive failure after oven cure; in another embodiment, the overlap shear strength is at least 11 MPa with cohesive failure; and in another embodiment the overlap shear strength is at least 15 MPa with cohesive failure.
In one embodiment, the stoichometric amine to epoxy ratio of the amine curing agent to the epoxy resin is from 0.2 to 0.9; in a preferred embodiment the stoichometric amine to epoxy ratio of the amine curing agent to the epoxy resin is from 0.3 to 0.7.
The invention provides a method of adhering to an oily metal substrate comprising applying a curable, structural epoxy adhesive composition to an oily metal substrate, wherein said curable, structural epoxy adhesive composition comprises two parts, the first part comprising:
(a) an epoxy catalyst comprising:
(i) a Ca+2 salt; and (ii) diazobicyclo(2,2,2)-octane as an epoxy polymerization catalyst; and (b) an amine curing agent; and the second part comprising an epoxy resin having an average epoxide functionality of greater than one.
-PCTYtTS95/I 1900 EPOXY ADHESIVE COMPOSITION
FIELD OF THE INVENTION
The present invention relates to a thermally curable two part epoxy composition. The invention also relates to a two part epoxy adhesive made from the epoxy composition.
BACKGROUND OF THE INVENTION
Epoxy compositions are used widely in industry as adhesives, paints, and coatings for a number of applications. Epoxy adhesives are particularly useful for bonding metal surfaces together to provide strong structural bonds.
Structural epoxy adhesives have replaced spot welding and other methods of mechanical fastening in many industrial applications, such as in automotive assembly plants.
In some applications, it is often desirable to induction cure an epoxy adhesive composition for a short period of time so that the adhesive develops a green strength sufficient to bond metal surfaces. The induction cure generally involves a short exposure to radio frequency energy, on the order of magnitude of less than a minute, and often less than about 10 seconds, which generates heat in the metal parts to start the curing reaction. During this time, the epoxy adhesive catalyst needs to be activated to start the curing of the adhesive. Curing of the adhesive to its final state, i.e., a structural adhesive, is usually done in a subsequent oven bake.
Catalysts which have sufficient reactivity for induction curing often have a very limited pot Life; other catalysts may not effect sufficient curing to build the desired green strength during the induction heating cycle. It is desirable for the epoxy adhesive to build a strong, robust bond to the metal surface, usually through an oily coating of a mill oil, cutting fluid, draw oil, or a combination thereof. A
bond is referred to as robust if the bond breaks apart cohesively at high shear values when tested in an overlap shear test. The bonds may break in three different modes:
(1) the adhesive splits apart, leaving portions of the adhesive adhered to both metal surfaces in a cohesive failure mode; (2) the adhesive pulls away from either metal surfaces in an adhesive failure mode, or (3) a combination of adhesive and cohesive failure. Optimally, the adhesive fails in either the cohesive failure mode, or a combination of adhesive and cohesive failure.
There remains an ongoing need for improved epoxy adhesives that build robust, cohesive failure bonds to oily metals.
SL>ZvIMARY OF THE INVENTION
The present invention provides an epoxy catalyst comprising:
(i) an inorganic metal salt; and (ii) an epoxy polymerization catalyst. In a preferred embodiment the epoxy catalyst comprises a calcium salt and a non-sterically hindered tertiary amine such as dimethylbenzyl amine, dimethyl octyl amine, tributyl amine, diazobicyclo-(2,2,2)-octane and tris-2,4,6,-(dimethylaminomethyl)phenol.
The invention also provides an amine curing agent for epoxy resins comprising:
(i) the epoxy catalyst; and (ii) an amine curing agent.
The invention also provides a two-part amine curing epoxy composition that is capable of bonding to oily metal surfaces to form robust, structural bonds, comprising:
(I) a first part comprising:
an epoxy resin curing agent comprising:
(i) a catalytically effective amount of the epoxy catalyst having an inorganic metal salt; and an epoxy homopolymerization catalyst; and (ii) an amine curing agent; and (II) a second part comprising an epoxy resin having an average epoxide functionality of greater than one.
Preferably, the adhesive composition further includes a toughening agent compatible with the epoxy composition.
The present invention also provides a method of adhering to an oily metal substrate comprising applying a curable, structural epoxy adhesive , composition to an oily metal substrate.
.. _2-WO 96109352 f3 PCT/US95/I1900 DETAILED DESCRIPTION
The epoxy compositions of the invention are provided in a two part system in which the first part comprises a catalyst and an amine curing agent, and the second part comprises the epoxide.
The catalyst of the invention comprises a metal salt and a compound that is effective in lowering the first peak exotherm on curing of the epoxy composition as determined on a differential scanning calorimeter (DSC) at a heating rate of 20°C per minute. Preferably, the first peak exotherm is lowered by at least 20°C and more preferably by at least 3S°C as compared to compositions having only the metal salt, only the catalyst, or neither. Preferably, the curing agent will also erect a lowering of the second peak exotherm temperature, and most preferably, the second peak exotherm is lowered to less than about 250°C.
The invention provides a method of adhering to an oily metal substrate comprising applying a curable, structural epoxy adhesive composition to an oily metal substrate, wherein said curable, structural epoxy adhesive composition comprises two parts, the first part comprising:
(a) an epoxy catalyst comprising:
(i) a Ca+Z salt; and (ii) an epoxy polymerization catalyst having the structure of formula (I):
R~
R4 ~ CI) wherein R' is H or -CH3 .
R2 is -CHNRsR6 and R5 and R6 are independently selected from -CH3 and -y CH2CH3;
R3 and R4 independently may be present or absent, when present R3 and R4 are -CHNRsR6 and Rs and R6 are independently selected from -CH3 and -CH2CH3;
and (b) an amine curing agent; and the second part comprising an epoxy resin having an average epoxide functionality of greater than one. In one embodiment, Rl is H; in another Rz is -CHN(CH3)2, and in a third R3 and R4 are present and each of Ra, R3, and R4 is -CHN(CH3)Z. In another embodiment,the structure of formula (I) is tris 2,4,6-(dimethylaminomethyl)phenol. In a preferred embodiment, every epoxy polymerization catalyst that is present in the composition has the structure of formula (n.
In one embodiment, the adhesive composition has an overlap shear strength as measured by the test method Initial Shear Strength After Induction Heating for Examples 3 and 19 (described below) of at least 0.2 MPa after induction cure plus 1 hour of room temperature cure; in a preferred embodiment the overlap shear strength is at least 0.5 MPa.
In another embodiment, the adhesive composition has an overlap shear strength as measured by the test method Lap Shear Strength (described below) of at least 9 MPa and cohesive failure after oven cure; in another embodiment, the overlap shear strength is at least 11 MPa with cohesive failure; and in another embodiment the overlap shear strength is at least 15 MPa with cohesive failure.
In one embodiment, the stoichometric amine to epoxy ratio of the amine curing agent to the epoxy resin is from 0.2 to 0.9; in a preferred embodiment the stoichometric amine to epoxy ratio of the amine curing agent to the epoxy resin is from 0.3 to 0.7.
The invention provides a method of adhering to an oily metal substrate comprising applying a curable, structural epoxy adhesive composition to an oily metal substrate, wherein said curable, structural epoxy adhesive composition comprises two parts, the first part comprising:
(a) an epoxy catalyst comprising:
(i) a Ca+2 salt; and (ii) diazobicyclo(2,2,2)-octane as an epoxy polymerization catalyst; and (b) an amine curing agent; and the second part comprising an epoxy resin having an average epoxide functionality of greater than one.
WO 96/09352 ,_ ~ ~ PCT/US95fii900 Useful metal salts include compounds having as the metal ion, Ca+i, Mg+Z, Bi+3, Ce+3, Fe+3, Pb+', Cu+2, Co+a, La+3, Li+', In+3, Th+4, Be+2, Ba+a, Sr+2, and Zn+2. Preferably, the metal ion is Ca+a, Mg+i, or La+3; in a more preferred embodiment, the metal ion is Ca+2. Counter ions in the metal salts that have proven useful include N03, CF3S03, CI04, BF4, CH3C6H~S0z, and SbF6, with N03, CF3S03, CH3C6H4S02, and C104 being preferred.
In the practice of the invention, an amine curing agent is used in an amount sufficient to cure the epoxy adhesive composition. This amount is an approximate stoichiometric amount based on the type of epoxy resin used.
Useful stoichometric ratios of amine:epoxy range from about 0.2 to about 0.9. The amount typically ranges from about 5 to 200 parts by weight of curing agent per 100 parts of the total amount of epoxide used.
Suitable base curing agents include polyamide resins, aliphatic amines, polyether diamines, aromatic amines, and mercaptan resins. Specific examples of base curing agents are the Ancamide~ Series of products, commercially available from Air Products and Chemical Company, and the Scherex Series, commercially available from Schering-Berling.
Also useful are polyaminopolyamide, also referred to as polyamido amine, curing agents, which are commercially available or may be prepared as disclosed in U.S. Patent No. 3,257,342 (Kwong). The curing agents disclosed in U.S. Patent No. 3,257,342 (Kwong) are amino-terminated polyamides that are the reaction product of a diaminopolyether and a polycarboxylic acid. Preferred carboxylic acids include dimer fatty acids or a mixture of dimer and trimer fatty acids. These carboxylic acids are available from Henkle Corporation under the EmpolTM tradename, and include EmpoITM 1022, EmpoITM 1018, and EmpoITM 1014.
The polyamidoamines can also be prepared as follows:
(1) Charge the acid to a reactor and heat to about 75°C to about 100°C under a low vacuum of about -28 inches Hg.
(2) Charge amine to the reactor under reduced pressure.
(3) Add nitrogen to bring reactor to atmospheric pressure.
(4) Heat slowly to about 175°C, distilling the water of reaction during heating.
In the practice of the invention, an amine curing agent is used in an amount sufficient to cure the epoxy adhesive composition. This amount is an approximate stoichiometric amount based on the type of epoxy resin used.
Useful stoichometric ratios of amine:epoxy range from about 0.2 to about 0.9. The amount typically ranges from about 5 to 200 parts by weight of curing agent per 100 parts of the total amount of epoxide used.
Suitable base curing agents include polyamide resins, aliphatic amines, polyether diamines, aromatic amines, and mercaptan resins. Specific examples of base curing agents are the Ancamide~ Series of products, commercially available from Air Products and Chemical Company, and the Scherex Series, commercially available from Schering-Berling.
Also useful are polyaminopolyamide, also referred to as polyamido amine, curing agents, which are commercially available or may be prepared as disclosed in U.S. Patent No. 3,257,342 (Kwong). The curing agents disclosed in U.S. Patent No. 3,257,342 (Kwong) are amino-terminated polyamides that are the reaction product of a diaminopolyether and a polycarboxylic acid. Preferred carboxylic acids include dimer fatty acids or a mixture of dimer and trimer fatty acids. These carboxylic acids are available from Henkle Corporation under the EmpolTM tradename, and include EmpoITM 1022, EmpoITM 1018, and EmpoITM 1014.
The polyamidoamines can also be prepared as follows:
(1) Charge the acid to a reactor and heat to about 75°C to about 100°C under a low vacuum of about -28 inches Hg.
(2) Charge amine to the reactor under reduced pressure.
(3) Add nitrogen to bring reactor to atmospheric pressure.
(4) Heat slowly to about 175°C, distilling the water of reaction during heating.
WO 96/09352 PCT/US95/11900~
(5) At about 175°C to about 200°C, apply a vacuum of about -25 to about -40 inches Hg and distill for about an hour.
(5) At about 175°C to about 200°C, apply a vacuum of about -25 to about -40 inches Hg and distill for about an hour.
(6) Add nitrogen to bring reactor to atmospheric pressure and discharge product.
S Epoxides useful in the practice of the invention can be any organic compound having at least one oxirane ring that is polymerizable by ring opening, i.e., an average epoxy functionality greater than one, and preferably at least two.
The epoxides can be monomeric or polymeric, and aliphatic, cycloaliphatic, heterocyclic, aromatic, or mixtures thereof. The preferred epoxides are aromatic and contain more than 1.5 epoxy groups per molecule and preferably 2 or more epoxy groups per molecule.
The useful materials have a molecular weight of about 150 to 10,000 and preferably from about 300 to 1,000. Useful materials include linear polymeric epoxides having terminal epoxy groups (e.g., a diglycidyl ether of a polyoxyalkylene glycol), polymeric epoxides having skeletal epoxy groups (e.g., polybutadiene polyepoxy), and polymeric epoxides having pendant epoxy groups (e.g., a glycidyl methacrylate polymer or copolymer), and mixtures thereof.
Useful epoxide-containing materials include compounds of the general Formula II:
R'(OCH2-C~ ~ H2)n (I~
O
wherein:
R' is alkyl, alkyl ether, or aryl, preferably aryl and n is an integer between 2 and 6. Preferred are aromatic glycidyl ethers such as those prepared by reacting a polyhydric phenol with an excess of epichlorohydrin. Examples of useful phenols include resorcinol, catechol, hydroquinone, and the polynuclear phenols including p,p'-dihydroxydibenzyl, p,p'-dihydroxydiphenyl, p,p'-dihydroxydiphenyl sulfone, p,p'-dihydroxybenzophenone, 2,2'-dihydroxy-1,1-dinaphthylmethane, and the 2,2', 2,3', 2,4', 3,3', 3,4', and 4,4' isomers of dihydroxydiphenylmethane, dihydroxydiphenyldimethylmethane, dihydroxydiphenylethylmethylmethane, dihydroxydiphenylmethylpropylmethane, dihydroxydiphenylethylphenylmethane, WO 96109352 s~ PCT/US95/11900 dihydroxydiphenylpropylphenylmethane, dihydroxydiphenylbutylphenylmethane, dihydroxydiphenyltolylmethane, dihydroxydiphenyltolylmethylmethane, dihydroxydiphenyldicyclohexylmethane, and dihydroxydiphenylcyclohexane. Also preferred are polyhydric phenolic formaldehyde condensation products as well as polyglycidyl ethers that contain as reactive groups only epoxy groups or hydroxy groups.
Compounds of the above general Formula II, but wherein n=1, are also useful as optional additives in the composition of the instant invention.
Further, the useful materials for the invention include diglycidyl ethers of the bisphenol A and of novolak resins, such as described in "Handbook of Epoxy Resins" by Lee and Nevill, McGraw-Hill Book Co., New York (1967).
Epoxides with flexibilized backbones are also useful. Preferred materials include diglycidyl ethers of bisphenol A and diglycidyl ethers of bisphenol F, and most preferably diglycidyl ethers of bisphenol A, because of the desirable structural adhesive properties that these materials attain upon curing.
Examples of commercially available epoxides useful in the invention include diglycidyl ethers of bisphenol A (e.g., those available under the trademarks Epon 828, Epon 1001, and Epon 1310 from Shell Chemical Co., and DER-331, DER-332, and DER-334, available from Dow Chemical Co.); diglycidyl ethers of bisphenol F (e.g., Epiclon~830, available from Dai Nippon Ink and Chemicals Inc.); silicone resins containing diglycidyl epoxy functionality; flame retardant epoxy resins (e.g., DER 580, a brominated bisphenol type epoxy resin available from Dow Chemical Co.); and 1,4-butanediol diglycidyl ethers.
The toughening agents which are useful in the present invention include polymeric compounds having both a rubbery phase and a thermoplastic phase, such as graft copolymers having a polymerized diene rubbery core and a polyacrylate or polymethacrylate shell; graft copolymers having a rubbery core with a polyacrylate or polymethacrylate shell; and elastomeric particles polymerized in situ in the epoxide from free-radical polymerizable monomers and a copolymeric stabilizer.
Specific examples of useful toughening agents include graft copolymers having a polymerized dime rubbery backbone or core which is grafted '~~~'~ ~ PCTlUS95/11900~
to a shell of an acrylic acid ester or methacrylic acid ester, monovinyl aromatic hydrocarbon, or a mixture thereof, such as disclosed in U.S. Patent No.
3,496,250, incorporated herein by reference. Preferable rubbery backbones comprise polymerized butadiene or a polymerized mixture of butadiene and styrene.
Preferable shells comprising polymerized methacrylic acid esters are lower alkyl (C1-C4) substituted methacrylates. Preferable monovinyl aromatic hydrocarbons are styrene, alpha-methylstyrene, vinyltoluene, vinylxylene, ethylvinylbenzene, isopropylstyrene, chlorostyrene, dichlorostyrene, and ethylchlorostyrene.
Further examples of useful toughening agents are acrylate core-shell graft copolymers wherein the core or backbone is a polyacrylate polymer having a glass transition temperature (T8) below about 0°C, such as polybutyl acrylate or polyisooctyl acrylate to which is grafted a polymethacrylate polymer (shell) having a T8 about 25°C, such as polymethylmethacrylate.
Still further examples of toughening agents useful in the invention are elastomeric particles that have a Tg below about 25°C and have been polymerized in situ in the epoxide before mixing with the other components of the composition. These elastomeric particles are polymerized from free-radical polymerizable monomers and a copolymerizable polymeric stabilizer that is soluble in the epoxide. The free-radical polymerizable monomers are ethylenically unsaturated monomers or diisocyanates combined with co-reactive difunctional hydrogen compounds such as diols, diamines, and alkanolamines. Examples of these elastomeric particles are disclosed in U.S. Patent No. 4,525,181. These particles are commonly referred to as "organosols".
Still other toughening agents are rubber modified liquid epoxy resins.
An example of such a resin is Kraton'~"~ RP6565 Rubber available from Shell Chemical Company. The modified epoxy resin is made from 85% by weight Epon~ 828 and 15% by weight of a KratonTT' rubber. The Kraton~ rubbers are known in the industry as elastomeric block copolymers.
A further class of toughening agents includes rubbery copolymers that have reactive functional groups, such as amine terminated butadiene copolymers.
_g_ WO 96109352 ~ PCT/US951II900 The toughening agent is preferably used in an amount equal to about 3 to 35 parts by weight, and more preferably about 5 to 15 parts by weight per parts by weight of the epoxy resin. The toughening agents of the present invention add strength to the composition after curing without interfering with curing of the epoxide.
In some cases reactive diluents may be added to control the flow characteristics of the adhesive composition. Suitable diluents have at least one reactive terminal end portion and preferably, a saturated or unsaturated cyclic backbone. Preferred reactive terminal ether portions include glycidyl ether and vinyl ether. Examples of suitable diluents include the diglycidyl ether of resorcinol, diglycidyl ether of cyclohexane dimethanol, diglycidyl ether of neopentyl glycol, triglycidyl ether of trimethylolpropane dipentene, and the divinyl ether of cyclohexanedimethanol. Commercially available reactive diluents are "WC-68"
from Rhone Poulenc, and Rapicure'~ CHVE, a divinyl ether of cyclohexanedimethanol available from Allied-Signal Corp. of Morristown, NJ.
Various other adjuvants can be added to the epoxide composition to enhance properties of the composition before and after curing.
Also included among useful adjuvants are nonreactive diluents;
plasticizers such as conventional phosphates and phthalates; thixotropic agents such as fumed silica to provide flow control; pigments to enhance color tones such as fernc oxide, brick dust, carbon black, and titanium dioxide; fillers such as talc, silica, magnesium, calcium sulfate, beryllium aluminum silicate; clays such as bentonite; glass and ceramic beads and bubbles; and reinforcing materials, such as woven and nonwoven webs of organic and inorganic fibers such as polyester, polyimide, glass fibers, and ceramic fibers. The adjuvants can be added in an amount effective for the intended purpose; typically, amounts up to about 50 parts of adjuvant per total weight of formulation can be used.
The epoxy composition of the present invention may be formulated in a variety of ways. By providing a two-part composition, in which the first part contains all of the catalyst components, with the two parts being combined prior to use of the composition, desirable shelf life or pot-life of the composition is obtained. In some applications, it is desirable to select the amounts and the WO 96/09352 ~ PCT/US95/11900 distribution of the ingredients in each part to provide viscosity control and better mixing of the two parts. For example, the fillers can be divided so that each part contains a portion of the fillers used.
The epoxy compositions of the present invention can be cured by any means which allow sufficient heat to start the curing reaction. The means can include ambient temperature, conventional ovens, induction heating, infrared , radiation, microwave radiation, immersion into liquid baths, or any combination thereof. Typically, the final curing is conducted at a temperature in the range of about 50°C to about 200°C for a time ranging from about 1 second to about 2 hours. The curing time will depend upon the particular process for curing.
Induction heating times typically range from about 1-60 seconds while oven curing times can range from about 0.1 to about 2 hours.
The epoxy adhesive of the present invention can be used for bonding metal to metal, plastic to plastic, and plastic to metal. Examples of metal surfaces include steel, titanium, oily steel, aluminum, and magnesium. Plastic surfaces include polyethylene, polycarbonate, polyester, polyurethane, and ureaformaldehyde. The epoxy adhesive can be used in assembling parts such as for automobiles, aircraft, refrigeration units, etc.
The following non-limiting examples serve to further illustrate the present invention in greater detail.
REACTIVITY OF THE ADHESIVE
The reactivity of the adhesive is a measure of how quickly the adhesive is cured when heated.
The reactivity is determined on a difFerential scanning calorimeter (DSC Model 912 available from DuPont). Approximately 10-15 milligrams of the adhesive is placed in the DSC and heated from 30°C to 350°C at a heating rate of 20°C per minute.
The test results are plotted in a graph of heat flow in Watts/gram vs temperature in degrees C. From the plots, the following information is recorded:
(A) Number of peaks generated;
(B) Maximum exotherm temperatures from each peak; and W096109352 , ~ PCTlUS95/ii900 (C) Area under each curve (joules/gram) (D) Total area under both curves (Jlgram) IlvTITIAL LAP SHEAR STRENGTH AFTER INDUCTION HEATING FOR
This test is a measure of the green strength that develops after an induction heating cycle. A test sample is prepared by applying the adhesive to 2.54 cm by 10.16 cm overlapping oily steel strips and curing as detailed below. The metal strips are 0.85 mm thick G-60HDES (hot dipped extra smooth galvanized steel) available from ACT. The strips are prepared for testing by wiping with methyl ethyl ketone and covering with Quaker 61-MAL-HCL-1 from Quaker Chemical Co. draw lubricant at a coating weight of 400 milligrams per square foot.
The strips are left at room temperature for at least 20 minutes before testing.
The adhesive composition (mixed in a volume ratio of 2 parts B to 1 part A) is mixed with about 1% glass beads ("MicrobeadTM 1402 Class IV
Engineering Grade", available from Cataphote, Inc.) to provide a 0.25 mm thick bond. The adhesive is then applied, within 30 minutes of mixing, to a 1.27 cm area on one end of one strip of metal, and a second strip of metal is placed so that 1.27 cm of one end of the second strip overlaps the adhesive, and with the uncoated ends of each strip extending in opposing directions. The strips are clamped together and the test sample is induction cured in a Miller Induction Heating System available from Miller Electric Manufacturing Co., Appleton, WI. The system includes a model IHPSS 10-5 Induction Heating power system, a model INCA 25-50 induction heating controller, and a Radiator 1A cooling system. The sample is placed in the induction heating unit, heated for 4 seconds with the induction heating coil to achieve a bondline temperature of about 275°C, and held at room temperature for the specified time, i.e., 15 minutes, 30 minutes, 60 minutes, or 24 hours before testing (Reported as "Induction Cure + 15 minutes", etc.).
The test is conducted at room temperature on an InstronTM tester with a jaw separation speed of 1.27 mm per minute with a 5.08 mm jaw gap. The data is reported in MegaPascals (MPa) and represents an average of at least three test samples from the composition. The mode of failure is also noted as adhesive, (A), wherein the adhesive pulls cleanly away from the metal strip, cohesive, (C), WO 96/09352 ~ PCT/LTS95/11900 wherein the adhesive splits and part of the adhesive is left on each of the metal strips, or mixed, (N)7, wherein the failure mode is partly adhesive and partly cohesive.
EXAMPLES
Example 1 Part A of a 2-part adhesive composition was prepared by mixing 40 parts of an amine-terminated polyamide (the reaction product of a diamine having the formula:
HaN-CHZ-CH2-CH2-(-O-CHa-CH2-)2-O-CHZ-CH2-CH2-NH2 and a dimer acid mixture (Empo1TM1014 available from Henkel Corp) in a 2:1 equivalents ratio), 6.0 parts 4,7,10-trioxatridecane 1,3-diamine (H221 available from BASF), 8.0 parts 2,4,6-tri dimethylaminomethyl phenol (K-54 available from Anchor Corp.), 2.0 parts calcium nitrate, 2.5 parts imidazole, and heating to about 175 to 200°F to form a solution. The solution was cooled to below about 43°C and 16.0 parts amine terminated butadiene rubber (ATBN 1300X16 available from B.
F.
Goodrich Co.) were added. The rubber can be heated as needed to a temperature below about 43°C to enhance dispersion. Also added were 20 parts amorphous silicon dioxide (GP-71, available from Harbison-Walker Corp.) and 3.0 parts fumed silica (Cab-O-Sil~ TS-720, available from Cabot Corp.) using a high shear mixer.
Part B of the 2-part epoxy adhesive composition was prepared by mixing together 15 parts of methacrylate butadiene styrene terpolymer (ParaloidTMEXL2691, available from Rohm & Haas Co.) with 80 parts of a diglycidyl ether of bisphenol A (EponTM828, available from Shell Chemical ,Co.) and heating at about 80°C for about 60 minutes with constant stirnng. As the mixture was cooling, 20 parts diglycidyl ether of cyclohexanedimethanol were added (Heloxy MK 107 made by Rhone Poulenc). The mixture was then cooled to about room temperature and the following were added and mixed with a high shear mixer:
2.5 parts epoxy silane (Z-6040 available from Union Carbide, Inc.), 2.0 parts fumed silica (Cab-O-SiITMTS-730), 3.0 parts glass beads having a nominal particle size of about 0.25 mm (available from Cataphote, Inc.), 20 parts amorphous silicon dioxide (GP-71 ) and 19.7 parts glass bubbles (B37/2000 available from Minnesota Mining WD 96/09352 ~ ~ PCTIUS95/11900 and Manufacturing Co.), and 5.0 parts of calcium ion-exchanged silica gel (SHlELDEXTMACS, available from W.R. Grace & Co.).
An adhesive composition was prepared by mixing a 2:1 volume ratio of Part B:Part A, and tested for induction cure strength as detailed above.
Test results are shown in Table 1.
EXAMPLE 1 Induction Cure Strength (MPa)/Failure Mode Induction Cure + 15 minutes 13/C
Induction Cure + 30 minutes 12/C
Induction Cure + 60 minutes 12/C
Induction Cure + 24 hours 19/C
INITIAL LAP SHEAR STRENGTH AFTER INDUCTION HEATING FOR
This test is a measure of the green strength that develops after an induction heating cycle. A test sample is prepared by applying the adhesive to 2.54 cm by 10.16 cm overlapping oily steel strips and curing as detailed below. The metal strips are 0.85 mm thick G-60HDES (hot dipped extra smooth galvanized steel) available from ACT. The strips are prepared for testing by wiping with methyl ethyl ketone and covering with Novamax FB27-MC-1 from Novamax Chemical Co., draw lubricant at a coating weight of 1,500 milligrams per square foot. The strips are left at room temperature for at least 30 minutes before testing.
The adhesive composition mixed in a weight ratio to achieve the desired amine to epoxy stoichiometry contains about 1 % glass beads ("MicrobeadTM 1402 Class IV Engineering Grade" available from Cataphote, Inc.) to provide a 0.25 mm thick bond. The adhesive is then applied, within 30 minutes of mixing, to a 1.27 cm area on one end of one strip of metal, and a second strip of metal is placed so that 1.27 cm of one end of the second strip overlaps the adhesive, and with the uncoated ends of each strip extending in opposing directions. The strips are clamped together and the test sample is induction cured in a Miller WO 96/09352 PCT/US95/11900' Induction Heating System available from Miller Electric Manufacturing Co., Appleton, WI. The system includes a model IHPSS 10-5 Induction Heating power system, a model INCA 25-50 induction heating controller, and a Radiator 1 A
cooling system. The sample is placed in the induction heating unit, heated for seconds with the induction heating coil to achieve a bondline temperature of about 121°C, and held at room temperature for a specified time, i.e., 15 minutes, 30 minutes, 60 minutes, or 24 hours before testing (Reported as "Induction Cure +
minutes", etc.).
Example 3 had a lap shear strength of 0 and Example 19 had a lap shear strength of 1.4 MPa after induction cure at 121 C for 5 seconds and a 15 minute dwell at room temperature.
LAP SHEAR STRENGTH
This test is a measure of the shear strength of an adhesive after final curing. The mixed adhesive composition is applied to oily metal coupons as described above and then allowed to cure at room temperature overnight. The next day, the bonded assemblies are each oven cured at 163°C for 20 minutes.
The bonds are allowed to equilibrate to room temperature and then tested for overlap shear as described below.
The test is conducted at room temperature on an InstronTM tester with a jaw separation speed of 1.27 cm per minute with a 5.08 cm jaw gap. The data is reported in megaPascals (IVIPa) and represents an average of at least three test samples from the composition. The mode of failure is also noted as adhesive, (A), wherein the adhesive pulls cleanly away from the metal strip, cohesive, (C), wherein the adhesive splits and part of the adhesive is left on each of the metal strips, or mixed, (M), wherein the failure mode is partly adhesive and partly cohesive.
Part A of a 2-part adhesive composition was prepared by mixing 40 parts of an amine-terminated polyamide (the reaction product of a diamine having the formula:
WO 96/09352 , ~ PCTlZTS95/d d900 ,, HZN-CHz-CHz-CH2-(-O-CH2-CH2-)z-O-CHz-CHz-CHz-NHz and a dimer acid mixture (EmpolTM 1014 available from Henkel Corp) in a 2:1 equivalents ratio), 6.0 parts 4,7,10-trioxatridecane-1,3-diamine (H221 available from BASF) to form a solution. Then 16.0 parts amine terminated butadiene rubber (ATBN 1300X16 available from B. F. Goodrich Co.). The rubber can be heated as needed to a temperature below about 45C to enhance dispersion. Also added were 5 parts amorphous silicon dioxide (GP-71, available from Harbison-Walker Corp.) and 1.0 parts fumed silica (Cab-O-Sil~ TS-720, available from Cabot Corp.) using a high shear mixer.
Part B of the 2-part epoxy adhesive composition was prepared by mixing together 15 parts of methacrylate butadiene styrene terpolymer (ParaloidTMEXL2691, available from Rohm & Haas Co.) with 80 parts of a diglycidyl ether of bisphenol A (EponTM828, available from Shell Chemical Co.) and heating at about 80°C for about 60 minutes with constant stirring. As the mixture was cooling, 20 parts diglycidyl ether of cyclohexanedimethanol (Heloxy MK 107 made by Rhone Poulenc). The mixture was then cooled to about room temperature and the following were added and mixed with a high shear mixer: 3.0 parts glass beads having a nominal particle size of about 0.25mm (available from Cataphote, Inc.), and 10 parts amorphous silicon dioxide (GP-71 ).
An adhesive composition was prepared by mixing a 1:1.8 weight ratio of Part A:Part B. The amine/epoxy ratio was 0.6. The adhesive was tested for Reactivity and Lap Shear Strength according to test procedures described above. Test results are shown in Table 2.
Part A of a 2-part adhesive composition was prepared by mixing 40 parts of an amine-terminated polyamide (the reaction product of a diamine having the formula:
H2N-CHz-CHz-CHz-(-O-CHz-CHz-)z-O-CHz-CHz-CHz-NHz and a dimer acid mixture (EmpolTM1014 available from Henkel Corp) in a 2:1 equivalents ratio), 6.0 parts 4,7,10-trioxatridecane 1,3-diamine (Ii221 available from BASF), and 8.0 parts tris-2,4,6-(dimethylaminomethyl)phenol (K-54 available WO 96/09352 , ~ :~ ~' ~ ' PCT/US95/11900~
U .il ..r from Anchor Corp.) to form a solution. Then 16.0 parts amine terminated butadiene rubber (ATBN 1300X16 available from B.F. Goodrich Co.) were added.
The rubber can be heated as needed to a temperature below about 45C to enhance dispersion. Also added were 5 parts amorphous silicon dioxide (GP-71, available from Harbison-Walker Corp.) and 1.0 parts fumed silica (Cab-O-Sil~ TS-720, available from Cabot Corp.) using a high shear mixer.
Epoxy adhesive compositions were prepared as described in Example 2. Example 3 had an amine/epoxy ratio of 0.6 and the adhesive was prepared by mixing a 1:1.8 weight ratio of Part A:Part B. Example 4 had an amine/epoxy raio of 0.3 and the adhesive was prepared by mixing a 1:3.6 weight ratio of PartA:Part B. The adhesives were tested as in Example 2 and test results are shown in Table 2.
Part A of a 2-part adhesive composition was prepared by mixing 40 parts of an amine-terminated polyamide (the reaction product of a diamine having the formula:
HZN-CH2-CHZ-CHa-(-O-CHI-CHa-)2-O-CHa-CHZ-CH2-NHz and a dimer acid mixture (Empo1TM1014 available from Henkel Corp) in a 2:1 equivalents ratio), 6.0 parts 4,7,10-trioxatridecane 1,3-diamine (H221 available from BASF), 3.0 parts calcium triflate, and heating to about 79°C to 93°C to form a solution. The solution was cooled to below about 43°C and 16.0 parts amine terminated butadiene rubber (ATBN 1300X16 available from B. F. Goodrich Co.) were added. The rubber can be heated as needed to a temperature below about 43°C to enhance dispersion. Also added were 5 parts amorphous silicon dioxide (GP-71, available from Harbison-Walker Corp.) and 1.0 parts fumed silica (Cab-O-Sil~ TS-720, available from Cabot Corp.) using a high shear mixer.
Adhesives were prepared and tested as described in Examples 3 and 4. Test results are shown in Table 2.
WO 96109352 ~ ~ PCT/fJS951I1900 Part A of a 2 part adhesive composition was prepared as in Example 2. Various catalysts, as shown in Table 2 were added in an amount of 10% by weight of Part A. All of the amine compounds used as part of the catalyst were obtained from Aldrich Chemical Co.
Epoxy adhesives were then prepared as described in Examples 3 and 4. Test results are shown in Table 2.
The data show that a preferred combination of Ca+Z salt and tris-2,4,6-(dimethylaminomethyl)phenol yielded a lower total area under the DSC
curves. This preferred combination also yielded the most induction reactive adhesive that has the ability to fail cohesively from oily metal substrates in an overlap shear test after oven cure.
r -1~_ .
WO 96/09352 ~ PCT/US95/11900~
Ex Catalyst Reactivity AminelEpoxy Lap A/B/C Ratio Shear Stren h 2 No Catalyst A=1; B=126C; 0.60 No cure C=99J/
3 K-54 only A=1; B=130C; 0.60 15/A
C= 161J/
4 K-54 only A=1; B=128C; 0.30 18/C
C=IOSJI
CaTriflate only A=2; 0.60 No cure B=113C,279C;
C=160,61J/g, D=221 J/
6 CaTriflate only A=2; 0.30 No cure B= 114,307C;
C=91,155J/g, D=246 J/
S Epoxides useful in the practice of the invention can be any organic compound having at least one oxirane ring that is polymerizable by ring opening, i.e., an average epoxy functionality greater than one, and preferably at least two.
The epoxides can be monomeric or polymeric, and aliphatic, cycloaliphatic, heterocyclic, aromatic, or mixtures thereof. The preferred epoxides are aromatic and contain more than 1.5 epoxy groups per molecule and preferably 2 or more epoxy groups per molecule.
The useful materials have a molecular weight of about 150 to 10,000 and preferably from about 300 to 1,000. Useful materials include linear polymeric epoxides having terminal epoxy groups (e.g., a diglycidyl ether of a polyoxyalkylene glycol), polymeric epoxides having skeletal epoxy groups (e.g., polybutadiene polyepoxy), and polymeric epoxides having pendant epoxy groups (e.g., a glycidyl methacrylate polymer or copolymer), and mixtures thereof.
Useful epoxide-containing materials include compounds of the general Formula II:
R'(OCH2-C~ ~ H2)n (I~
O
wherein:
R' is alkyl, alkyl ether, or aryl, preferably aryl and n is an integer between 2 and 6. Preferred are aromatic glycidyl ethers such as those prepared by reacting a polyhydric phenol with an excess of epichlorohydrin. Examples of useful phenols include resorcinol, catechol, hydroquinone, and the polynuclear phenols including p,p'-dihydroxydibenzyl, p,p'-dihydroxydiphenyl, p,p'-dihydroxydiphenyl sulfone, p,p'-dihydroxybenzophenone, 2,2'-dihydroxy-1,1-dinaphthylmethane, and the 2,2', 2,3', 2,4', 3,3', 3,4', and 4,4' isomers of dihydroxydiphenylmethane, dihydroxydiphenyldimethylmethane, dihydroxydiphenylethylmethylmethane, dihydroxydiphenylmethylpropylmethane, dihydroxydiphenylethylphenylmethane, WO 96109352 s~ PCT/US95/11900 dihydroxydiphenylpropylphenylmethane, dihydroxydiphenylbutylphenylmethane, dihydroxydiphenyltolylmethane, dihydroxydiphenyltolylmethylmethane, dihydroxydiphenyldicyclohexylmethane, and dihydroxydiphenylcyclohexane. Also preferred are polyhydric phenolic formaldehyde condensation products as well as polyglycidyl ethers that contain as reactive groups only epoxy groups or hydroxy groups.
Compounds of the above general Formula II, but wherein n=1, are also useful as optional additives in the composition of the instant invention.
Further, the useful materials for the invention include diglycidyl ethers of the bisphenol A and of novolak resins, such as described in "Handbook of Epoxy Resins" by Lee and Nevill, McGraw-Hill Book Co., New York (1967).
Epoxides with flexibilized backbones are also useful. Preferred materials include diglycidyl ethers of bisphenol A and diglycidyl ethers of bisphenol F, and most preferably diglycidyl ethers of bisphenol A, because of the desirable structural adhesive properties that these materials attain upon curing.
Examples of commercially available epoxides useful in the invention include diglycidyl ethers of bisphenol A (e.g., those available under the trademarks Epon 828, Epon 1001, and Epon 1310 from Shell Chemical Co., and DER-331, DER-332, and DER-334, available from Dow Chemical Co.); diglycidyl ethers of bisphenol F (e.g., Epiclon~830, available from Dai Nippon Ink and Chemicals Inc.); silicone resins containing diglycidyl epoxy functionality; flame retardant epoxy resins (e.g., DER 580, a brominated bisphenol type epoxy resin available from Dow Chemical Co.); and 1,4-butanediol diglycidyl ethers.
The toughening agents which are useful in the present invention include polymeric compounds having both a rubbery phase and a thermoplastic phase, such as graft copolymers having a polymerized diene rubbery core and a polyacrylate or polymethacrylate shell; graft copolymers having a rubbery core with a polyacrylate or polymethacrylate shell; and elastomeric particles polymerized in situ in the epoxide from free-radical polymerizable monomers and a copolymeric stabilizer.
Specific examples of useful toughening agents include graft copolymers having a polymerized dime rubbery backbone or core which is grafted '~~~'~ ~ PCTlUS95/11900~
to a shell of an acrylic acid ester or methacrylic acid ester, monovinyl aromatic hydrocarbon, or a mixture thereof, such as disclosed in U.S. Patent No.
3,496,250, incorporated herein by reference. Preferable rubbery backbones comprise polymerized butadiene or a polymerized mixture of butadiene and styrene.
Preferable shells comprising polymerized methacrylic acid esters are lower alkyl (C1-C4) substituted methacrylates. Preferable monovinyl aromatic hydrocarbons are styrene, alpha-methylstyrene, vinyltoluene, vinylxylene, ethylvinylbenzene, isopropylstyrene, chlorostyrene, dichlorostyrene, and ethylchlorostyrene.
Further examples of useful toughening agents are acrylate core-shell graft copolymers wherein the core or backbone is a polyacrylate polymer having a glass transition temperature (T8) below about 0°C, such as polybutyl acrylate or polyisooctyl acrylate to which is grafted a polymethacrylate polymer (shell) having a T8 about 25°C, such as polymethylmethacrylate.
Still further examples of toughening agents useful in the invention are elastomeric particles that have a Tg below about 25°C and have been polymerized in situ in the epoxide before mixing with the other components of the composition. These elastomeric particles are polymerized from free-radical polymerizable monomers and a copolymerizable polymeric stabilizer that is soluble in the epoxide. The free-radical polymerizable monomers are ethylenically unsaturated monomers or diisocyanates combined with co-reactive difunctional hydrogen compounds such as diols, diamines, and alkanolamines. Examples of these elastomeric particles are disclosed in U.S. Patent No. 4,525,181. These particles are commonly referred to as "organosols".
Still other toughening agents are rubber modified liquid epoxy resins.
An example of such a resin is Kraton'~"~ RP6565 Rubber available from Shell Chemical Company. The modified epoxy resin is made from 85% by weight Epon~ 828 and 15% by weight of a KratonTT' rubber. The Kraton~ rubbers are known in the industry as elastomeric block copolymers.
A further class of toughening agents includes rubbery copolymers that have reactive functional groups, such as amine terminated butadiene copolymers.
_g_ WO 96109352 ~ PCT/US951II900 The toughening agent is preferably used in an amount equal to about 3 to 35 parts by weight, and more preferably about 5 to 15 parts by weight per parts by weight of the epoxy resin. The toughening agents of the present invention add strength to the composition after curing without interfering with curing of the epoxide.
In some cases reactive diluents may be added to control the flow characteristics of the adhesive composition. Suitable diluents have at least one reactive terminal end portion and preferably, a saturated or unsaturated cyclic backbone. Preferred reactive terminal ether portions include glycidyl ether and vinyl ether. Examples of suitable diluents include the diglycidyl ether of resorcinol, diglycidyl ether of cyclohexane dimethanol, diglycidyl ether of neopentyl glycol, triglycidyl ether of trimethylolpropane dipentene, and the divinyl ether of cyclohexanedimethanol. Commercially available reactive diluents are "WC-68"
from Rhone Poulenc, and Rapicure'~ CHVE, a divinyl ether of cyclohexanedimethanol available from Allied-Signal Corp. of Morristown, NJ.
Various other adjuvants can be added to the epoxide composition to enhance properties of the composition before and after curing.
Also included among useful adjuvants are nonreactive diluents;
plasticizers such as conventional phosphates and phthalates; thixotropic agents such as fumed silica to provide flow control; pigments to enhance color tones such as fernc oxide, brick dust, carbon black, and titanium dioxide; fillers such as talc, silica, magnesium, calcium sulfate, beryllium aluminum silicate; clays such as bentonite; glass and ceramic beads and bubbles; and reinforcing materials, such as woven and nonwoven webs of organic and inorganic fibers such as polyester, polyimide, glass fibers, and ceramic fibers. The adjuvants can be added in an amount effective for the intended purpose; typically, amounts up to about 50 parts of adjuvant per total weight of formulation can be used.
The epoxy composition of the present invention may be formulated in a variety of ways. By providing a two-part composition, in which the first part contains all of the catalyst components, with the two parts being combined prior to use of the composition, desirable shelf life or pot-life of the composition is obtained. In some applications, it is desirable to select the amounts and the WO 96/09352 ~ PCT/US95/11900 distribution of the ingredients in each part to provide viscosity control and better mixing of the two parts. For example, the fillers can be divided so that each part contains a portion of the fillers used.
The epoxy compositions of the present invention can be cured by any means which allow sufficient heat to start the curing reaction. The means can include ambient temperature, conventional ovens, induction heating, infrared , radiation, microwave radiation, immersion into liquid baths, or any combination thereof. Typically, the final curing is conducted at a temperature in the range of about 50°C to about 200°C for a time ranging from about 1 second to about 2 hours. The curing time will depend upon the particular process for curing.
Induction heating times typically range from about 1-60 seconds while oven curing times can range from about 0.1 to about 2 hours.
The epoxy adhesive of the present invention can be used for bonding metal to metal, plastic to plastic, and plastic to metal. Examples of metal surfaces include steel, titanium, oily steel, aluminum, and magnesium. Plastic surfaces include polyethylene, polycarbonate, polyester, polyurethane, and ureaformaldehyde. The epoxy adhesive can be used in assembling parts such as for automobiles, aircraft, refrigeration units, etc.
The following non-limiting examples serve to further illustrate the present invention in greater detail.
REACTIVITY OF THE ADHESIVE
The reactivity of the adhesive is a measure of how quickly the adhesive is cured when heated.
The reactivity is determined on a difFerential scanning calorimeter (DSC Model 912 available from DuPont). Approximately 10-15 milligrams of the adhesive is placed in the DSC and heated from 30°C to 350°C at a heating rate of 20°C per minute.
The test results are plotted in a graph of heat flow in Watts/gram vs temperature in degrees C. From the plots, the following information is recorded:
(A) Number of peaks generated;
(B) Maximum exotherm temperatures from each peak; and W096109352 , ~ PCTlUS95/ii900 (C) Area under each curve (joules/gram) (D) Total area under both curves (Jlgram) IlvTITIAL LAP SHEAR STRENGTH AFTER INDUCTION HEATING FOR
This test is a measure of the green strength that develops after an induction heating cycle. A test sample is prepared by applying the adhesive to 2.54 cm by 10.16 cm overlapping oily steel strips and curing as detailed below. The metal strips are 0.85 mm thick G-60HDES (hot dipped extra smooth galvanized steel) available from ACT. The strips are prepared for testing by wiping with methyl ethyl ketone and covering with Quaker 61-MAL-HCL-1 from Quaker Chemical Co. draw lubricant at a coating weight of 400 milligrams per square foot.
The strips are left at room temperature for at least 20 minutes before testing.
The adhesive composition (mixed in a volume ratio of 2 parts B to 1 part A) is mixed with about 1% glass beads ("MicrobeadTM 1402 Class IV
Engineering Grade", available from Cataphote, Inc.) to provide a 0.25 mm thick bond. The adhesive is then applied, within 30 minutes of mixing, to a 1.27 cm area on one end of one strip of metal, and a second strip of metal is placed so that 1.27 cm of one end of the second strip overlaps the adhesive, and with the uncoated ends of each strip extending in opposing directions. The strips are clamped together and the test sample is induction cured in a Miller Induction Heating System available from Miller Electric Manufacturing Co., Appleton, WI. The system includes a model IHPSS 10-5 Induction Heating power system, a model INCA 25-50 induction heating controller, and a Radiator 1A cooling system. The sample is placed in the induction heating unit, heated for 4 seconds with the induction heating coil to achieve a bondline temperature of about 275°C, and held at room temperature for the specified time, i.e., 15 minutes, 30 minutes, 60 minutes, or 24 hours before testing (Reported as "Induction Cure + 15 minutes", etc.).
The test is conducted at room temperature on an InstronTM tester with a jaw separation speed of 1.27 mm per minute with a 5.08 mm jaw gap. The data is reported in MegaPascals (MPa) and represents an average of at least three test samples from the composition. The mode of failure is also noted as adhesive, (A), wherein the adhesive pulls cleanly away from the metal strip, cohesive, (C), WO 96/09352 ~ PCT/LTS95/11900 wherein the adhesive splits and part of the adhesive is left on each of the metal strips, or mixed, (N)7, wherein the failure mode is partly adhesive and partly cohesive.
EXAMPLES
Example 1 Part A of a 2-part adhesive composition was prepared by mixing 40 parts of an amine-terminated polyamide (the reaction product of a diamine having the formula:
HaN-CHZ-CH2-CH2-(-O-CHa-CH2-)2-O-CHZ-CH2-CH2-NH2 and a dimer acid mixture (Empo1TM1014 available from Henkel Corp) in a 2:1 equivalents ratio), 6.0 parts 4,7,10-trioxatridecane 1,3-diamine (H221 available from BASF), 8.0 parts 2,4,6-tri dimethylaminomethyl phenol (K-54 available from Anchor Corp.), 2.0 parts calcium nitrate, 2.5 parts imidazole, and heating to about 175 to 200°F to form a solution. The solution was cooled to below about 43°C and 16.0 parts amine terminated butadiene rubber (ATBN 1300X16 available from B.
F.
Goodrich Co.) were added. The rubber can be heated as needed to a temperature below about 43°C to enhance dispersion. Also added were 20 parts amorphous silicon dioxide (GP-71, available from Harbison-Walker Corp.) and 3.0 parts fumed silica (Cab-O-Sil~ TS-720, available from Cabot Corp.) using a high shear mixer.
Part B of the 2-part epoxy adhesive composition was prepared by mixing together 15 parts of methacrylate butadiene styrene terpolymer (ParaloidTMEXL2691, available from Rohm & Haas Co.) with 80 parts of a diglycidyl ether of bisphenol A (EponTM828, available from Shell Chemical ,Co.) and heating at about 80°C for about 60 minutes with constant stirnng. As the mixture was cooling, 20 parts diglycidyl ether of cyclohexanedimethanol were added (Heloxy MK 107 made by Rhone Poulenc). The mixture was then cooled to about room temperature and the following were added and mixed with a high shear mixer:
2.5 parts epoxy silane (Z-6040 available from Union Carbide, Inc.), 2.0 parts fumed silica (Cab-O-SiITMTS-730), 3.0 parts glass beads having a nominal particle size of about 0.25 mm (available from Cataphote, Inc.), 20 parts amorphous silicon dioxide (GP-71 ) and 19.7 parts glass bubbles (B37/2000 available from Minnesota Mining WD 96/09352 ~ ~ PCTIUS95/11900 and Manufacturing Co.), and 5.0 parts of calcium ion-exchanged silica gel (SHlELDEXTMACS, available from W.R. Grace & Co.).
An adhesive composition was prepared by mixing a 2:1 volume ratio of Part B:Part A, and tested for induction cure strength as detailed above.
Test results are shown in Table 1.
EXAMPLE 1 Induction Cure Strength (MPa)/Failure Mode Induction Cure + 15 minutes 13/C
Induction Cure + 30 minutes 12/C
Induction Cure + 60 minutes 12/C
Induction Cure + 24 hours 19/C
INITIAL LAP SHEAR STRENGTH AFTER INDUCTION HEATING FOR
This test is a measure of the green strength that develops after an induction heating cycle. A test sample is prepared by applying the adhesive to 2.54 cm by 10.16 cm overlapping oily steel strips and curing as detailed below. The metal strips are 0.85 mm thick G-60HDES (hot dipped extra smooth galvanized steel) available from ACT. The strips are prepared for testing by wiping with methyl ethyl ketone and covering with Novamax FB27-MC-1 from Novamax Chemical Co., draw lubricant at a coating weight of 1,500 milligrams per square foot. The strips are left at room temperature for at least 30 minutes before testing.
The adhesive composition mixed in a weight ratio to achieve the desired amine to epoxy stoichiometry contains about 1 % glass beads ("MicrobeadTM 1402 Class IV Engineering Grade" available from Cataphote, Inc.) to provide a 0.25 mm thick bond. The adhesive is then applied, within 30 minutes of mixing, to a 1.27 cm area on one end of one strip of metal, and a second strip of metal is placed so that 1.27 cm of one end of the second strip overlaps the adhesive, and with the uncoated ends of each strip extending in opposing directions. The strips are clamped together and the test sample is induction cured in a Miller WO 96/09352 PCT/US95/11900' Induction Heating System available from Miller Electric Manufacturing Co., Appleton, WI. The system includes a model IHPSS 10-5 Induction Heating power system, a model INCA 25-50 induction heating controller, and a Radiator 1 A
cooling system. The sample is placed in the induction heating unit, heated for seconds with the induction heating coil to achieve a bondline temperature of about 121°C, and held at room temperature for a specified time, i.e., 15 minutes, 30 minutes, 60 minutes, or 24 hours before testing (Reported as "Induction Cure +
minutes", etc.).
Example 3 had a lap shear strength of 0 and Example 19 had a lap shear strength of 1.4 MPa after induction cure at 121 C for 5 seconds and a 15 minute dwell at room temperature.
LAP SHEAR STRENGTH
This test is a measure of the shear strength of an adhesive after final curing. The mixed adhesive composition is applied to oily metal coupons as described above and then allowed to cure at room temperature overnight. The next day, the bonded assemblies are each oven cured at 163°C for 20 minutes.
The bonds are allowed to equilibrate to room temperature and then tested for overlap shear as described below.
The test is conducted at room temperature on an InstronTM tester with a jaw separation speed of 1.27 cm per minute with a 5.08 cm jaw gap. The data is reported in megaPascals (IVIPa) and represents an average of at least three test samples from the composition. The mode of failure is also noted as adhesive, (A), wherein the adhesive pulls cleanly away from the metal strip, cohesive, (C), wherein the adhesive splits and part of the adhesive is left on each of the metal strips, or mixed, (M), wherein the failure mode is partly adhesive and partly cohesive.
Part A of a 2-part adhesive composition was prepared by mixing 40 parts of an amine-terminated polyamide (the reaction product of a diamine having the formula:
WO 96/09352 , ~ PCTlZTS95/d d900 ,, HZN-CHz-CHz-CH2-(-O-CH2-CH2-)z-O-CHz-CHz-CHz-NHz and a dimer acid mixture (EmpolTM 1014 available from Henkel Corp) in a 2:1 equivalents ratio), 6.0 parts 4,7,10-trioxatridecane-1,3-diamine (H221 available from BASF) to form a solution. Then 16.0 parts amine terminated butadiene rubber (ATBN 1300X16 available from B. F. Goodrich Co.). The rubber can be heated as needed to a temperature below about 45C to enhance dispersion. Also added were 5 parts amorphous silicon dioxide (GP-71, available from Harbison-Walker Corp.) and 1.0 parts fumed silica (Cab-O-Sil~ TS-720, available from Cabot Corp.) using a high shear mixer.
Part B of the 2-part epoxy adhesive composition was prepared by mixing together 15 parts of methacrylate butadiene styrene terpolymer (ParaloidTMEXL2691, available from Rohm & Haas Co.) with 80 parts of a diglycidyl ether of bisphenol A (EponTM828, available from Shell Chemical Co.) and heating at about 80°C for about 60 minutes with constant stirring. As the mixture was cooling, 20 parts diglycidyl ether of cyclohexanedimethanol (Heloxy MK 107 made by Rhone Poulenc). The mixture was then cooled to about room temperature and the following were added and mixed with a high shear mixer: 3.0 parts glass beads having a nominal particle size of about 0.25mm (available from Cataphote, Inc.), and 10 parts amorphous silicon dioxide (GP-71 ).
An adhesive composition was prepared by mixing a 1:1.8 weight ratio of Part A:Part B. The amine/epoxy ratio was 0.6. The adhesive was tested for Reactivity and Lap Shear Strength according to test procedures described above. Test results are shown in Table 2.
Part A of a 2-part adhesive composition was prepared by mixing 40 parts of an amine-terminated polyamide (the reaction product of a diamine having the formula:
H2N-CHz-CHz-CHz-(-O-CHz-CHz-)z-O-CHz-CHz-CHz-NHz and a dimer acid mixture (EmpolTM1014 available from Henkel Corp) in a 2:1 equivalents ratio), 6.0 parts 4,7,10-trioxatridecane 1,3-diamine (Ii221 available from BASF), and 8.0 parts tris-2,4,6-(dimethylaminomethyl)phenol (K-54 available WO 96/09352 , ~ :~ ~' ~ ' PCT/US95/11900~
U .il ..r from Anchor Corp.) to form a solution. Then 16.0 parts amine terminated butadiene rubber (ATBN 1300X16 available from B.F. Goodrich Co.) were added.
The rubber can be heated as needed to a temperature below about 45C to enhance dispersion. Also added were 5 parts amorphous silicon dioxide (GP-71, available from Harbison-Walker Corp.) and 1.0 parts fumed silica (Cab-O-Sil~ TS-720, available from Cabot Corp.) using a high shear mixer.
Epoxy adhesive compositions were prepared as described in Example 2. Example 3 had an amine/epoxy ratio of 0.6 and the adhesive was prepared by mixing a 1:1.8 weight ratio of Part A:Part B. Example 4 had an amine/epoxy raio of 0.3 and the adhesive was prepared by mixing a 1:3.6 weight ratio of PartA:Part B. The adhesives were tested as in Example 2 and test results are shown in Table 2.
Part A of a 2-part adhesive composition was prepared by mixing 40 parts of an amine-terminated polyamide (the reaction product of a diamine having the formula:
HZN-CH2-CHZ-CHa-(-O-CHI-CHa-)2-O-CHa-CHZ-CH2-NHz and a dimer acid mixture (Empo1TM1014 available from Henkel Corp) in a 2:1 equivalents ratio), 6.0 parts 4,7,10-trioxatridecane 1,3-diamine (H221 available from BASF), 3.0 parts calcium triflate, and heating to about 79°C to 93°C to form a solution. The solution was cooled to below about 43°C and 16.0 parts amine terminated butadiene rubber (ATBN 1300X16 available from B. F. Goodrich Co.) were added. The rubber can be heated as needed to a temperature below about 43°C to enhance dispersion. Also added were 5 parts amorphous silicon dioxide (GP-71, available from Harbison-Walker Corp.) and 1.0 parts fumed silica (Cab-O-Sil~ TS-720, available from Cabot Corp.) using a high shear mixer.
Adhesives were prepared and tested as described in Examples 3 and 4. Test results are shown in Table 2.
WO 96109352 ~ ~ PCT/fJS951I1900 Part A of a 2 part adhesive composition was prepared as in Example 2. Various catalysts, as shown in Table 2 were added in an amount of 10% by weight of Part A. All of the amine compounds used as part of the catalyst were obtained from Aldrich Chemical Co.
Epoxy adhesives were then prepared as described in Examples 3 and 4. Test results are shown in Table 2.
The data show that a preferred combination of Ca+Z salt and tris-2,4,6-(dimethylaminomethyl)phenol yielded a lower total area under the DSC
curves. This preferred combination also yielded the most induction reactive adhesive that has the ability to fail cohesively from oily metal substrates in an overlap shear test after oven cure.
r -1~_ .
WO 96/09352 ~ PCT/US95/11900~
Ex Catalyst Reactivity AminelEpoxy Lap A/B/C Ratio Shear Stren h 2 No Catalyst A=1; B=126C; 0.60 No cure C=99J/
3 K-54 only A=1; B=130C; 0.60 15/A
C= 161J/
4 K-54 only A=1; B=128C; 0.30 18/C
C=IOSJI
CaTriflate only A=2; 0.60 No cure B=113C,279C;
C=160,61J/g, D=221 J/
6 CaTriflate only A=2; 0.30 No cure B= 114,307C;
C=91,155J/g, D=246 J/
7 CaT + Imidazole A=1; B=129C; 0.60 13/A
C=290 J/
C=290 J/
8 CaT + Imidazole A=1; B=146C; 0.30 14/A
C=296 J/
C=296 J/
9 CaT + 1,4 A=2; 0.60 10/A
Diazobicyclo(2,2,2)-B=110C,236C;
octane C=259, 8J/g, D=267 J/
CaT + 1,4 A=2; 0.30 15/M
Diazobicyclo(2,2,2)-B=120C, 297C;
octane C=223,30 J/g, D=253 J/
11 CaT + 4- A=1; 0.60 2/A
Dimethylamino- B=139C;
'dine C=247J/
12 CaT + 4- A=2; 0.30 14/A
Dimethylamino- B=126,258C;
pyridine C=205, 70J/g, D=275 J/
13 CaT + 1,5 A=2; 0.60 uncured Diazobicyclo B=125,286C;
(4,3,0)non-5-eneC=208, 30 J/g, D=23 8 J/
14 CaT + 1,5 A=2; 0.30 uncured Diazobicyclo B=125,327C;
(4,3,0)non-5-eneC=119,100 J/g, D=219 J/
WD 96!09352 PCT/US95/I I90~
15 CaT + 1,8 A=2; 0.60 12/A
Diazobicyclo(5,4,0)uB=123,3040;
ndec-7-ene C=193,40 J/g, D=233 J/
16 CaT + 1,8 A--2; 0.30 2/A
Diazobicyclo(5,4,0)uB=121,3220;
ndec-7-ene C=120,143 J/g, D=263 J/
17 CaT + A=2; 0.60 12/A
Dimethylbenzyl- B=120,3030;
amine C=166,46 J/g, D=212 J/
18 CaT + A--2; 0.30 14/0 Dimethylbenzyl- B=1200,3170;
amine C=100,130 J/g, D=23 0 J/
19 CaT + K-54 A--3; 0.60 11/A
B=106,122,2850 C=150,1 S
J/g, D=165 J/
20 CaT + K-54 A=2; 0.30 17/0 B=1240,311 C;
C=87,96 J/g, D=183J/
21 CaT + K-54 A=2; 0.45 14/A
B=124,3000;
C=117,61 J/g;
D=178 J/
22 CaT + K-54 A=2; 0.15 9/C
B=117,3620;
C=45,75 J/g D=120 J/
A = Number of peaks B = Maximum exotherm temperature of each peak C = Area under each curve (joules/gram) D = Total area under both curves (J/gram)
Diazobicyclo(2,2,2)-B=110C,236C;
octane C=259, 8J/g, D=267 J/
CaT + 1,4 A=2; 0.30 15/M
Diazobicyclo(2,2,2)-B=120C, 297C;
octane C=223,30 J/g, D=253 J/
11 CaT + 4- A=1; 0.60 2/A
Dimethylamino- B=139C;
'dine C=247J/
12 CaT + 4- A=2; 0.30 14/A
Dimethylamino- B=126,258C;
pyridine C=205, 70J/g, D=275 J/
13 CaT + 1,5 A=2; 0.60 uncured Diazobicyclo B=125,286C;
(4,3,0)non-5-eneC=208, 30 J/g, D=23 8 J/
14 CaT + 1,5 A=2; 0.30 uncured Diazobicyclo B=125,327C;
(4,3,0)non-5-eneC=119,100 J/g, D=219 J/
WD 96!09352 PCT/US95/I I90~
15 CaT + 1,8 A=2; 0.60 12/A
Diazobicyclo(5,4,0)uB=123,3040;
ndec-7-ene C=193,40 J/g, D=233 J/
16 CaT + 1,8 A--2; 0.30 2/A
Diazobicyclo(5,4,0)uB=121,3220;
ndec-7-ene C=120,143 J/g, D=263 J/
17 CaT + A=2; 0.60 12/A
Dimethylbenzyl- B=120,3030;
amine C=166,46 J/g, D=212 J/
18 CaT + A--2; 0.30 14/0 Dimethylbenzyl- B=1200,3170;
amine C=100,130 J/g, D=23 0 J/
19 CaT + K-54 A--3; 0.60 11/A
B=106,122,2850 C=150,1 S
J/g, D=165 J/
20 CaT + K-54 A=2; 0.30 17/0 B=1240,311 C;
C=87,96 J/g, D=183J/
21 CaT + K-54 A=2; 0.45 14/A
B=124,3000;
C=117,61 J/g;
D=178 J/
22 CaT + K-54 A=2; 0.15 9/C
B=117,3620;
C=45,75 J/g D=120 J/
A = Number of peaks B = Maximum exotherm temperature of each peak C = Area under each curve (joules/gram) D = Total area under both curves (J/gram)
Claims (15)
1. A method of adhering to an oily metal substrate comprising applying a curable, structural epoxy adhesive composition to an oily metal substrate, wherein said curable, structural epoxy adhesive composition comprises two parts, the first part comprising:
(a) an epoxy catalyst comprising:
(i) a Ca+2 salt; and (ii) an epoxy polymerization catalyst having a structure of formula (I):
wherein R1 is H or -CH3 R2 is -CHNR5R6 and R5 and R6 are independently selected from -CH3 and -CH2CH3;
R3 and R4 independently may be present or absent, when present R3 and R4 are -CHNR5R6 and R5 and R6 are independently selected from -CH3 and -CH2CH3; and (b) an amine curing agent; and the second part comprising an epoxy resin having an average epoxide functionality of greater than one and wherein the stoichiometric amine to epoxy ratio of the amine curing agent to the epoxy resin is from 0.2 to 0.9 and wherein the adhesive composition has an overlap shear strength of at least 9 MPa when said composition is applied to oily metal coupons having an emulsified draw lubricated coating weight of 1,500 mg/ft2 (16 x 10-3 kg/m2), cured at room temperature for 24 hours, oven cured for 20 minutes at 163°C, and then equilibrated to room temperature prior to measuring overlap shear strength as measured by the test method lap shear strength.
(a) an epoxy catalyst comprising:
(i) a Ca+2 salt; and (ii) an epoxy polymerization catalyst having a structure of formula (I):
wherein R1 is H or -CH3 R2 is -CHNR5R6 and R5 and R6 are independently selected from -CH3 and -CH2CH3;
R3 and R4 independently may be present or absent, when present R3 and R4 are -CHNR5R6 and R5 and R6 are independently selected from -CH3 and -CH2CH3; and (b) an amine curing agent; and the second part comprising an epoxy resin having an average epoxide functionality of greater than one and wherein the stoichiometric amine to epoxy ratio of the amine curing agent to the epoxy resin is from 0.2 to 0.9 and wherein the adhesive composition has an overlap shear strength of at least 9 MPa when said composition is applied to oily metal coupons having an emulsified draw lubricated coating weight of 1,500 mg/ft2 (16 x 10-3 kg/m2), cured at room temperature for 24 hours, oven cured for 20 minutes at 163°C, and then equilibrated to room temperature prior to measuring overlap shear strength as measured by the test method lap shear strength.
2. The method of claim 1, wherein R1 is H.
3. The method of claim 1 or 2, wherein R2 is - CHN (CH3) 2 .
4. The method of claim 1 or 2, wherein R3 and R4 are present and each of R2, R3, and R4 is -CHN (CH3) 2 .
5. The method of claim 1, wherein the structure of formula (I) is tris-2,4,5-(dimethylaminomethyl)phenol.
6. The method of any one of claims 1 to 5, wherein the Ca+2 salt has a counter ion selected from NO3, CF3SO3, CH3C6H4SO3, BF4, SbF6, Or ClO4.
7. The method of any one of claims 1 to 6, wherein every epoxy polymerization catalyst that is present in the composition has the structure of formula (I).
8. The method of any one of claims 1 to 7, wherein the composition further comprises a toughening agent.
9. The method of claim 8, wherein the toughening agent comprises an amine terminated butadiene copolymer.
10. The method of any one of claims 1 to 9, wherein the adhesive composition has an overlap shear strength of at least 0.2 MPa when said adhesive composition is applied to oily metal coupons having an emulsified draw lubricant coating weight of 1,50C mg/ft2, heated for 5 seconds with a capable induction heating coil to achieve a bondline temperature of about 121°C, and then cured at room temperature for 1 hour.
11. The method of any one of claims 1 to 9, wherein the adhesive composition has an overlap shear strength of at least 0.5 MPa when said adhesive composition is applied to oily metal coupons having an emulsified draw lubricant coating weight of 1,500 mg/ft2, heated for 5 seconds with a capable induction heating coil to achieve a bondline temperature of about 121°C, and then cured at room temperature for 1 hour.
12. The method of any one of claims 1 to 9, wherein the adhesive composition has an overlap shear strength as measured by the test method Lap Shear Strength of at least 11 MPa.
13. The method of any one of claims 1 to 9, wherein the adhesive composition has an overlap shear strength as measured by the test method Lap Shear Strength of at least 15 MPa.
14. The method of any one of claims 1 to 13, wherein the stoichiometric amine to epoxy ratio of the amine curing agent to the epoxy resin is from 0.3 to 0.7.
15. A method of adhering to an oily metal substrate comprising applying a curable, structural epoxy adhesive composition to an oily metal substrate, wherein said curable, structural epoxy adhesive composition comprises two parts, the first part comprising:
(a) an epoxy catalyst comprising:
( i ) a Ca+2 salt ; and (ii) diazobicyclo-(2,2,2)-octane as an epoxy polymerization catalyst; and (b) an amine curing agent; and the second part comprising an epoxy resin having an average epoxide functionality of greater than one.
(a) an epoxy catalyst comprising:
( i ) a Ca+2 salt ; and (ii) diazobicyclo-(2,2,2)-octane as an epoxy polymerization catalyst; and (b) an amine curing agent; and the second part comprising an epoxy resin having an average epoxide functionality of greater than one.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US30839094A | 1994-09-19 | 1994-09-19 | |
| US08/308390 | 1994-09-19 | ||
| PCT/US1995/011900 WO1996009352A1 (en) | 1994-09-19 | 1995-09-19 | Epoxy adhesive composition |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2198612A1 CA2198612A1 (en) | 1996-03-28 |
| CA2198612C true CA2198612C (en) | 2006-02-14 |
Family
ID=35892303
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002198612A Expired - Fee Related CA2198612C (en) | 1994-09-19 | 1995-09-19 | Epoxy adhesive composition |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2198612C (en) |
-
1995
- 1995-09-19 CA CA002198612A patent/CA2198612C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CA2198612A1 (en) | 1996-03-28 |
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